In every kind of inquiry, that cause alone must be supposed to act which we understand so far as to be able to appreciate its effects in particular circumstances, and compare them with fact, and see their perfect coincidence. If we have discovered causes, they are known as far as they are discovered. Their genuine effects are known, and therefore the phenomena which result from their agency are understood. When therefore it is acknowledged, as it must be acknowledged, that mankind have made but little advances in the knowledge of nature, notwithstanding the pretended discovery of causes by Aristotle, and the conducting clue of his philosophy, till of late years; and when it is also allowed that now, while we are every day making great additions to this subordinate knowledge, the causes which Aristotle has discovered are forgotten, and his philosophy is neglected; there is great room for suspecting (to say the least), that either the causes which philosophy pretends to have discovered are not real, or that Aristotle and his followers have not aimed at the discovery of causes, but only at the discovery of natural laws, and have failed in the attempt.

There seems here to be a previous question: Is it possible to discover a philosophical cause, that something which is neither the prior nor the posterior of the two immediately adjoining events, but their bond of union, and this distinct from the union itself? It is evident that this is an inquiry purely experimental. It is of human knowledge we speak. This must depend on the nature of the human mind. This is a matter of contingency, known to us only by experiment and observation. By observing all the feelings and operations of the mind, and classing and arranging them like any other object of science, we discover the general laws of human thought and human reasoning; and this is all the knowledge we can ever acquire of it, or of any thing else.

Much has been written on this subject. The most acute observation and sound judgment have been employed in the study; and we may venture to say, that considerable progress has been made in pneumatology. Many laws of human thought have been observed, and very distinctly marked; and philosophers are busily employed, some of them with considerable success, in the distribution of them into subordinate classes, so as to know their comparative extent, and to mark their distinguishing characters with a precision similar to what has been attained in botany and other parts of natural history; so that we may hope that this study will advance like others. But in all these researches, no phenomena have occurred which look like the perception or contemplation of these separate objects of thought, these philosophical causes, this power in abstracto. No philosopher has ever pretended to state such an object of the mind's observation, or attempted to group them into classes.

We may say at once, without entering into any detail, that those causes, those bonds of necessary union between the naturally conjoined events or objects, are not only perceived by means of the events alone, but are perceived solely in the events, and cannot be distinguished from the conjunctions themselves. They are neither the objects of separate observation, nor the productions of memory, nor inferences drawn from reflection on the laws by which the operation of our own minds are regulated; nor can they be derived from Bacon's other perceptions in the way of argumentative inference.

We cannot infer the paroxysm of terror from the appearance of impending destruction, or the fall of a stone when not supported, as we infer the incommensurability of the diagonal and side of a square. This last is implied in the very conception or notion of a square; not as a consequence of its other properties, but as one of its essential attributes: and the contrary proposition is not only false, but incapable of being distinctly conceived. This is not the case with the other phenomenon, or any matter of fact. The proofs which are brought of a mathematical proposition, are not the reason of its being true, but the steps by which this truth is brought into our view; and frequently, as in the instance now given, this truth is perceived, not directly, but consequentially, by the inconceivableness of the contrary proposition.

Mr Hume derives this irresistible expectation of Mr Hume's events from the known effect of custom, the association of ideas. The correlative event is brought into the mind by this well known power of custom, with that vivacity of conception which constitutes belief or expectation. But without insisting on the futility of his theory of belief, it is sufficient to observe, that this explanation begs the very thing to be proved, when it ascribes to custom a power of any kind. It is the origin of this very power which is the subject in dispute. Besides, on the genuine principles of scepticism, this custom involves an acknowledgement of past events, of a something different from present impressions, which, in this doctrine (if doctrine it can be called), are the only certain existences in nature: and, lastly, it is known that one clear experience is a sufficient foundation for this unshaken confidence and anticipation. General custom can never, on Mr Hume's principles, give superior vivacity to any particular idea.

This certain momentaneity of it as a separate object of observation, and this impossibility to derive this notion respecting of necessary and causal connection between the events casual of the universe from any source, have induced two of the most acute philosophers of Europe, Mr Leibnitz and Father Malebranche, to deny that there is any such connection, and to assert that the events of the universe go on in corresponding trains, but without any causal connection, just as a well regulated clock will keep time with the motions of the heavens without any kind of dependence on them. This harmony of events was pre-established by the Author of the Universe, in subserviency to the purposes he had in view in its formation.

All those purposes which are cognisable by us, may certainly be accomplished by this perfect adjustment. But without insisting on the fantastic wildness of this ingenious whim, it is quite enough to observe, that it also is a begging of the question, because it supposes causation when it ascribes all to the agency of the Deity.

Thus have we searched every quarter, without being able to find a source from which to derive this perception of a necessary connection among the events of the universe, or of this confident expectation of the continuance of physical laws; and yet we are certain of the feeling, and of the persuasion, be its origin what it may: for we speak intelligibly on this subject; we speak familiarly of cause, effect, power, energy, necessary connection, motives and their influence, argument and conviction, Such a knowledge is quite unnecessary, and therefore causes are no more cognisable by our intellectual powers than colours by a man born blind; nay, whoever will be at the pains to consider this matter agreeably to the received rules and maxims of logic, will find that necessary connection, or the bond of causation, can no more be the subject of philosophical discussion by man, than the ultimate nature of truth. It is precisely the same absurdity or incongruity, as to propose to examine light with a microscope. Other rational creatures may perceive them as easily as we hear sounds. All that we can say is, that their existence is probable, but by no means certain. Nay, it may be (and we may never know it) that we are not the efficient causes of our own actions, which may be effected by the Deity or by ministering spirits; and this may even be true in the material world. But all this is indifferent to the real occupation of the philosopher, and does not affect either the certainty, the extent, or the utility of the knowledge which he may acquire.

We are now able to appreciate the high pretensions of the philosopher, and his claim to scientific superiority, of the philosopher. We now see that this can neither be founded on any scientific superiority of his object, nor of his employment, very His object is not causes; and his discoveries are nothing but the discovery of general facts, the discovery of physical laws; and his employment is the same with that of the descriptive historian. He observes and describes with care and accuracy the events of nature; and then he groups them into classes, in consequence of resembling circumstances, detected in the midst of many others which are dissimilar and occasional. By gradually throwing out more circumstances of resemblance, he renders his classes more extensive; and, by carefully marking those circumstances in which the resemblance is observed, he characterises all the different classes; and, by a comparison of these with each other, in respect to the number of resembling circumstances, he distributes his classes according to their generality and subordination; thus exhausting the whole assemblage, and leaving nothing unarranged but accidental varieties. In this procedure it is to be remarked, that every grouping of similar events is, ipso facto, discovering a general fact, a physical law; and the expression of this assemblage is the expression of the physical law. And as every observation of this constancy of fact affords an opportunity for exerting the instinctive inference of natural connection between the related subjects, every such observation is the discovery of a power, property, or quality, of natural substance. And from what has been said, this observation of event is all we know of the connection, all we know of the natural power. And when the philosopher proceeds farther to the arrangement of events, according to their various degrees of complication, he is, ipso facto, making an arrangement of all natural powers according to their various degrees of subordinate influence. And thus his occupation is perfectly similar to that of the descriptive historian, classification and arrangement; and this constitutes all the science attainable by both.

Philosophy may therefore be defined, the study of the phenomena of the universe, with a view to discover the general laws which indicate the powers of natural substances, to explain subordinate phenomena, and to improve improve art: Or, in compliance with that natural instinct so much spoken of, Philosophy is the study of the phenomena of the universe, with a view to discover their causes, to explain subordinate phenomena, and to improve art.

The task is undoubtedly difficult, and will exercise our noblest powers. The employment is manly in itself, and the result of it important. It therefore justly merits the appellation of philosophy, although its objects are nowise different from what occupy the attention of other men.

The employment of the philosopher, like that of the natural historian, is threefold; DESCRIPTION, ARRANGEMENT and REFERENCE; while the objects are not things but events.

The description, when employed about events, may be more properly termed history. A philosophical history of nature consists in a complete or copious enumeration and narration of facts, properly selected, cleared of all unnecessary or extraneous circumstances, and accurately narrated. This constitutes the materials of philosophy. We cannot give a better example of this branch of philosophical occupation than astronomy.

From the beginning of the Alexandrian school to this day, astronomers have been at immense pains in observing the heavenly bodies, in order to detect their true motions. This has been a work of prodigious difficulty; for the appearances are such as might have been exhibited although the real motions had been extremely different. Not that our senses give us false information; but we form hasty, and frequently false judgments, from these informations; and call those things deceptions of sense, which are in fact errors of judgment. But the true motions have at last been discovered, and have been described with such accuracy, that the history may be considered as nearly complete. This is to be found in the usual systems of astronomy, where the tables contain a most accurate and synoptical account of the motion; so that we can tell with precision in what point of the heavens a planet has been seen at any instant that can be named.

Sir Isaac Newton's Optics is such another perfect model of philosophical history, as far as it goes. This part of philosophy may be called PHENOMENOLOGY.

Having in this manner obtained the materials of philosophical description, we must put them into a compendious and perspicuous form, so that a general knowledge of the universe may be easily acquired and firmly retained. This is to be done by classification and arrangement, and this classification must proceed on resemblances observed in the events; and the subsequent arrangement must be regulated by the distinctions of which those resemblances are still susceptible. This assemblage of events into groups must be expressed. They are facts; therefore the expression must be propositions. These propositions must be what the logicians call general or abstract propositions; for they express, not any individual fact of the assemblage, but that circumstance in which they all resemble. Such propositions are the following:

Proof is accompanied by belief; kindness is accompanied by gratitude; impulse is accompanied by motion. These are usually called general facts; but there are none such; every fact is individual. This language, however inaccurate, is very safe from misconstruction, and we may use it without scruple. These propositions are NATURAL OR PHYSICAL LAWS; and then the View of detecting and marking those resemblances in event, is Bacon's investigation of physical laws; and we may denominate this employment of the philosopher INVESTIGATION.

In the prosecution of this task, it will be found that the similarities of fact are of various extent; and thus we shall form physical laws of various extent; and we shall also find that some are subordinate to others; for the resemblance of a number of facts in one circumstance does not hinder a part of them from also resembling in another circumstance; and thus we shall find subordinations of fact in the same way as of quiescent qualities. And it is found here, as in natural history, that our assemblage of resembling events will be the more extensive as the number of resembling circumstances is smaller; and thus we shall have kingdoms, classes, orders, genera, and species of phenomena, which are expressed by physical laws of all those different ranks.

It has been already observed, that this observation of physical laws is always accompanied by a reference of that uniformity of event to a natural bond of union between the concomitant facts which is conceived by us as the cause of this concomitancy; and therefore this procedure of the philosopher is considered as the discovery of those causes, that is, the discovery of those powers of natural substances which constitute their physical relations, and may justly be called their distinguishing qualities or properties. This view of the matter gives rise to a new nomenclature and language. We give to those powers generic names, such as sensibility, intelligence, irritability, gravity, elasticity, fluidity, magnetism, &c. These terms, without exception, mark resembling circumstances of event; and no other definition can be given of them but a description of these circumstances. In a few cases which have been the subjects of more painful or refined discussion, we have proceeded farther in this abbreviation of language.

We have framed the verb "to gravitate," and the verbal noun "gravitation," which purely expresses the fact, the phenomenon; but is conceived to express the operation or energy of the cause or natural power. It is of importance to keep in mind this metaphysical remark on these terms; for a want of attention to the pure meaning of the words has frequently occasioned very great mistakes in philosophical science.

We may with propriety call this part of the philosopher's employment ATTIOLOGY.

We shall give an instance of its most successful application to the class of events already adduced as an example of philosophic history or phenomenology.

Kepler, a celebrated Prussian astronomer, having maturely considered the phenomena recorded in the tables and observations of his predecessors, discovered, amidst all the varieties of the planetary motions, three circumstances of resemblance, which are now known by the name of Kepler's laws.

1. All the planets describe ellipses, having the sun in one focus.

2. The elliptic areas described by a planet in the different parts of its orbit, are proportional to the times of description.

3. The squares of the periodic times are proportional to the cubes of the mean distances from the sun. By this observation or discovery, the study of the planetary motions were greatly promoted, and the calculation of their appearances was now made with a facility and an accuracy which surpassed all hopes: for the calculation of the place of a planet at any proposed instant was reduced to the geometrical problem of cutting off an area from an ellipse of known dimensions, which should bear the same proportion to the whole area, as the time for whose duration the motion is required, has to the known time of a complete revolution.

Long after this discovery of Kepler, Sir Isaac Newton found that these laws of Kepler were only particular cases of a fact or law still more general. He found that the deflections of the planets from uniform rectilinear motion were all directed to the sun; and that the simultaneous deflections were inversely proportional to the squares of the distances from that body.

Thus was established a physical law of vast extent: but further observation showed him, that the motion of every body of the solar system was compounded of an original motion of projection, combined with a deflection towards every other body; and that the simultaneous deflections were proportional to the quantity of matter in the body towards which they were directed, and to the reciprocal of the square of the distance from it. Thus was the law made still more general. He did not stop here. He compared the deflection of the moon in her orbit with the simultaneous deflection of a stone thrown from the hand, and describing a parabola; and he found that they followed the same law, that is, that the deflection of the moon in a second, was to that of the stone in the same time, as the square of the stone's distance from the centre of the earth, to the square of the moon's distance from it. Hence he concluded, that the deflection of a stone from a straight line was just a particular instance of the deflections which took place through the whole solar system.

The deflection of a stone is one of the indications it gives of its being gravis or heavy; whence he calls it gravitation. He therefore expresses the physical law which obtains through the whole solar system, by saying that "every body gravitates to every other body;" and the gravitations are proportional to the quantity of matter in that other body, and inversely proportional to the square of the distance from it."

Thus we see how the arrangement of the celestial phenomena terminated in the discovery of physical laws; and that the expression of this arrangement is the law itself.

Since the fall of a heavy body is one instance of the physical law, and since this fall is considered by all as the effect of its weight, and this weight is considered as the cause of the fall, the same cause is assigned for all the deflections observed in the solar system; and all the matter in it is found to be under the influence of this cause, or to be heavy: and thus his doctrine has been denominated the system of universal gravitation.

Philosophers have gone farther, and have supposed that gravity is a power, property, or quality, residing in all the bodies of the solar system. Sir Isaac Newton does not expressly say so, at least in that work where he gives an account of these discoveries. He contents himself with the immediate consequence of the first axiom in natural philosophy, viz. that every body remains in a state of rest, or of uniform rectilinear motion, unless affected by some moving force. Since the bodies of the solar system are neither in a state of rest, nor of uniform rectilinear motion, they must be considered as so affected; that is, that there operates on every one of them a moving force, directed towards all the others, and having the proportions observed in the deflection.

Other philosophers have endeavoured to show, that this general fact, detected by Sir Isaac Newton, is included in another still more general, viz. that every body moves which is impelled by another body in motion. They assert, that all the bodies of the solar system are continually impelled by a fluid which they call ether, which is moving in all places, and in all directions, or in circular vortices, and hurries along with it the planets and all heavy bodies. It would seem that the familiarity of motion produced by impulse, at least in those instances in which our own exertions are most employed, has induced philosophers to adopt such notions; perhaps, too, they are influenced by an obscure and indistinct notion affixed to the term action, as applied to changes in the material world, and which has given rise to an axiom, "that a body cannot act at a distance, or where it is not;" and thus have thought themselves obliged to look out for an immediate and contiguous agent in all those phenomena.

But the philosophers who profess to be most scrupulous in their adherence to the rules of philosophic discussion, deny the legitimacy of this pretended investigation of causes, saying that this doctrine is in direct opposition to the procedure of the mind in acquiring the knowledge of causes. Since the fact of impulse is not really observed in the celestial deflections, nor in the motions of heavy bodies, the law cannot be inferred. They say that it is not even necessary to show that the phenomena of the celestial motions are unlike the phenomena of impulse, although this can be done in the completest manner. It is enough that neither the fluid nor the impulse are observed; and therefore they are in the right when they assert, that there is inherent in, or accompanies all the bodies of the system, a power by which they deflect to one another. See Optics.

The debate is foreign to our present purpose, which is only to show how the observation and arrangement of phenomena terminates in the discovery of their causes, or the discovery of the powers or properties of natural substances.

This is a task of great difficulty, as it is of great importance. There are two chief causes of this difficulty.

1. In most of the spontaneous phenomena of nature there is a complication of many events, and some of them escape our observation. Attending only to the most obvious or remarkable, we conjoin these only in our imagination, and are apt to think these the concomitant events in nature, the proper indication of the cause, and the subjects of this philosophical relation, and to suppose that they are always conjoined by nature. Thus it was thought that there resided in a vibrating chord a power by which the sensation of sound was excited, or that a chord had a sounding quality. But it appears clearly from observation that there is an inconceivable number of events interposed between the vibration of the chord and the sensitive affection of our ear; and therefore, that sound is not the effect of the vibration of the chord, but of the very last event of this series: and this is completely pletely demonstrated by showing that the vibration and sound are not necessarily connected, because they are not always connected, but require the interposition of air or of some other elastic body.

These observations show the necessity of the most accurate and minute observation of the phenomena, that none of those intermediate events may escape us, and we be thus exposed to the chance of imaginary connections between events which are really far asunder in the procedure of nature. As the study has improved, mistakes of this kind have been corrected; and philosophers are careful to make their trains of events under one name as short as possible. Thus, in medicine, a drug is no longer considered as a specific remedy for the disease which is sometimes cured when it has been used, but is denominated by its most immediate operation on the animal frame: it is no longer called a febrifuge, but a sudorific.

2. When many natural powers combine their influence in a spontaneous phenomenon of nature, it is frequently very difficult to discover what part of the complicated effect is the effect of each; and to state those circumstances of similarity which are the foundation of a physical law, or entitle us to infer the agency of any natural power. The most likely method for insuring success in such cases is to get rid of this complication of event, by putting the subject into such a situation that the operation of all the known powers of nature shall be suspended, or so modified as we may perfectly understand their effects. We can thus appreciate the effects of such as we could neither modify nor suspend, or we can discover the existence of a new law, the operation of a new power.

This is called making an experiment; and is, of all, the most effectual way of advancing in the knowledge of nature, and has been called experimental philosophy.

It seems, however, at first sight, in direct opposition to the procedure of nature in forming general laws. These are formed by induction from multitudes of individual facts, and must be affirmed to no greater extent than the induction on which they are founded. Yet it is a matter of fact, a physical law of human thought, that one simple, clear, and unequivocal experiment, gives us the most complete confidence in the truth of a general conclusion from it to every similar case. Whence this anomaly? It is not an anomaly or contradiction of the general maxim of philosophical investigation, but the most refined application of it. There is no law more general than this, that "Nature is constant in all her operations." The judicious and simple form of our experiment insures se (we imagine) in the complete knowledge of all the circumstances of the event. Upon this supposition, and this alone, we consider the experiment as the faithful representative of every possible case of the conjunction. This will be more minutely considered afterwards.

The last branch of philosophic occupation is the explanation of subordinate phenomena. This is nothing more than the referring any particular phenomenon to that class in which it is included; or, in the language of philosophy, it is the pointing out the general law, or that general fact of which the phenomenon is a particular instance. Thus the feeling of the obligations of virtue is thought to be explained, when it is shown to be a particular case of that regard which every person has for his dearest interests. The rise of water in pumps is explained, when we show it to be a particular case of the pressure of fluids, or of the air. The general law under which we show it to be properly arranged is called the principle of the explanation, and the explanation itself is called the theory of the phenomenon. Thus Euler's explanation of the lunar irregularities is called a theory of the lunar motions on the principle of gravitation.

This may be done either in order to advance our own knowledge of nature, or to communicate it to others. If done with the first view, we must examine the phenomenon minutely, and endeavour to detect every circumstance in it, and thus discover all the known laws of nature which concur in its production; then we appreciate the operation of each according to the circumstances of its exertion; we then combine all these, and compare the result with the phenomenon. If they are similar, we have explained the phenomenon. We cannot give a better example than Franklin's explanation of the phenomena of thunder and lightning. See Lightning, and Electricity Index.

If we explain a phenomenon from known principles, we proceed synthetically from the general law already established and known to exert its influence in the present instance. We state this influence both in kind and degree according to the circumstances of the case; and, having combined them, we compare the result with the phenomenon, and show their agreement, and thus it is explained. Thus, because all the bodies of the solar system mutually gravitate, the moon gravitates to the sun as well as to the earth, and is continually, and in a certain determinate manner, deflected from that part which she would describe did she gravitate only to the earth. Her motion round the earth will be retarded during the first and third quarters of her orbit, and accelerated during the second and fourth. Her orbit and her period will be increased during our winter, and diminished during our summer. Her apogee will advance, and her nodes will recede; and the inclination of her orbit will be greatest when the nodes are in syzygy, and least when they are in quadrature. And all these variations will be in certain precise degrees. Then we show that all these things actually obtain the lunar motions, and they are considered as explained.

This summary account of the object and employment in all philosophical discussion is sufficient for pointing out its place in the circle of the sciences, and will serve to direct us to the proper methods of prosecuting it with success. Events are its object; and they are considered as connected with each other by causation, which may therefore be called the philosophical relation of things. The following may be adopted as the fundamental proposition on which all philosophical discussion proceeds, and under which every philosophical discussion or discovery may be arranged:

"Every change that we observe in the state or condition of things is considered by us as an effect, indicating the agency, characterising the kind, and determining the degree of its inferred cause."

As thus enounced, this proposition is evidently a physical law of human thought. It may be enounced as a necessary and independent truth, by saying, every change in the state and condition of things is an effect, &c. And accordingly it has been so enounced by Dr Reid*; and its title to this denomination has been abundantly supported by him. But we have no occasion to consider it as possessing this quality. We are speaking of philosophy, which is something contingent, depending on the existence and constitution of an intellectual being such as man; and, in conformity to the view which we have endeavoured to give of human knowledge in the subjects of philosophical relation, it is quite sufficient for our purpose that we maintain its title to the rank of an universal law of human thought. This will make it a first principle, even although it may not be a necessary truth.

All the proof necessary for this purpose is universality of fact; and we believe this to be without exception. We are not to expect that all mankind have made, or will ever make, a formal declaration of their opinion; but we may venture to say that all have made it, and continually do make it, virtually. What have the philosophers of all ages been employed about but the discovery of the causes of those changes that are incessantly going on? *Nil turpis physicis (says Cicero) quam fieri sine causâ quidquam decreverit.* Human curiosity has been directed to nothing so powerfully and so constantly as to this. Many absurd causes have been assigned for the phenomena of the universe; but no set of men have ever said that they happened without a cause. This is so repugnant to all our propensities and instincts, that even the atheistical sect, who, of all others, would have profited most by the doctrine, have never thought of advancing it. To avoid so shocking an absurdity, they have rather allowed that chance, that the concourse of atoms, are the causes of the beautiful arrangements of nature. The thoughtless vulgar are no less solicitous than the philosophers to discover the cause of things; and the poet expresses the natural and instinctive passion of all men, when he says,

*Felix qui potuit rerum cognoscere causas.*

And this anxiety is not to nourish, but to get rid of superstitious fears: for thus

*metus omnes, et inexorabile fatum*

*Subjecit pedibus, strepitumque Acherontis avari.*

Had men never speculated, their conduct alone gives sufficient evidence of the universality of the opinion. The whole conduct of man is regulated by it, nay, almost wholly proceeds upon it, in the most important matters, and where experience seems to leave us in doubt: and to act otherwise, as if anything whatever happened without a cause, would be a declaration of insanity. Dr Reid has beautifully illustrated this truth, by observing, that even a child will laugh at you if you try to persuade him that the top, which he misses from the place where he left it, was taken away by nobody. You may persuade him that it was taken away by a fairy or a spirit; but he believes no more about this nobody, than the master of the house when he is told that nobody was the author of any piece of theft or mischief. What opinion would be formed, says Dr Reid, of the intellects of the jurymen, on a trial for murder by persons unknown, who should say that the fractured skull, the watch and money gone, and other like circumstances, might possibly have no cause? he would be pronounced insane or corrupted.

We believe that Mr Hume is the first author who has ventured to call the truth of this opinion in question; and even he does it only in the way of mere possibility. He acknowledges the generality of the opinion; and he only objects to the foundation of this generality: and contra he objects to it merely because it does not quadrature with his theory of belief; and therefore it may happen that Mr Hume some men may have no such opinion. But it must be observed on this occasion, that the opinion of a philosopher is of no greater weight in a case like this than that of a ploughboy. If it be a first principle, directing the opinions and actions of all, it must operate on the minds of all. The philosopher is the only person who may chance to be without it: for it requires much labour, and long habits resolutely maintained, to warp our natural sentiments; and experience shows us that they may be warped if we are at sufficient pains. It is also worthy of remark, that this philosopher seems as much under the influence of this law as ordinary mortals. It is only when he is aware of its not tallying with his other doctrines that his scruples appear. Observe how with great he speaks when off his guard: "As to those impressions which arise from the senses, their ultimate cause ency. is, in my opinion, perfectly inexplicable by human reason; and it will always be impossible to decide with certainty whether they arise immediately from the object, are produced by the creative power of the mind, or are derived from the Author of our being."

Among these alternatives he never thought of their not being derived from any cause.

But it is not enough to show that this is a physical law of the human mind: we have assumed it as a first principle, the foundation of a whole science; therefore not included in or derived from any thing more general. Mr Hume's endeavours to prove that it is not a necessary truth, show with sufficient evidence that most attempts to derive it in the way of argument are petitiones principii; a thing very commonly met with in all attempts to prove first principles. It cannot be proved this by induction of facts that every event has a cause, because induction always supposes an observed fact or first event. Now in by far the greatest number of events the causes are unknown. Perhaps in no event what-proof ever do we know the real cause, or that power or energy which, without any intervention, produces the effect. No man can say, that in the simplest event which he ever observed, he was fully apprised of every circumstance which concurred to its production. We suppose that no event in nature can be adduced more simple than the motion of a suspended glass ball when gently struck by another glass ball; and we imagine that most of our readers will say that he perfectly sees everything which happens in this phenomenon. We believe, too, that most of our readers are of opinion that a body is never put in motion but by the impulse of another, except in the cases of animal motion; and that they are disposed to imagine that magnets put iron in motion, and that an electrified body moves another, by means of an interposed though invisible fluid somehow circulating round them. Now we must inform such readers, that unless the stroke has been very smart, so smart indeed as to shatter the glass balls, the motion of the suspended ball was produced without impulse: that is, the two balls were not in contact during the stroke; and the distance between them was not less than the 9000th part of an inch, and probably much greater. We must say farther, that it is not certain that even the most violent stroke, such as would shatter them to pieces, is enough to bring them into real contact. The proofs of this singular position are too long for this place; but the evidence will be sufficiently seen by consulting the article Optics.

Unless, therefore, our readers are willing to allow that the suspended ball was put in motion by a repulsive force inherent in one or both balls, they must acknowledge that they do not fully know all the circumstances of this so simple phenomenon, or all the train of events which happen in it; and therefore they are reduced to the necessity of supposing, although they do not see it, an intervening fluid or matter, by the immediate action of whose adjoining particles the motion is produced.

This being the case in the simplest phenomenon that we can pitch upon, what shall we say of the numberless multitudes which are incomparably more complex? Must we not acknowledge that the efficient causes, even in the vulgar sense of the word, the immediately preceding events, are unknown, because the conjunctions are not observed? and therefore it cannot be said that it is from experimental induction that this truth gains universal belief. Experience, so far from supporting it as a direct proof, seems rather the strongest argument against it; for we have no experiment of unquestionable authority but the narrow circle of our own power exerted on our thoughts and actions. And even here there are perhaps cases of change where we cannot say with certainty that we perceive the efficient cause.

Nothing seems to remain, therefore, but to allow that this physical law of human judgment is instinctive, a constituent of the human soul, a first principle; and incapable of any other proof than the appeal to the feelings of every man.

Simply to say, that every change is considered as an effect, is not giving the whole characters of this physical law. The cause is not always, perhaps never, observed, but inferred from the phenomena. The inference is therefore in every instance dependant on the phenomenon. The phenomenon is to us the language of nature: It is therefore the sole indication of the cause and of its agency: it is therefore the indication of the very cause, and of no other. The observed change therefore characterises the cause and marks its kind. This is confirmed by every word of philosophical language, where, as has already been observed, the names of the inferred powers of nature are nothing but either abbreviated descriptions of the phenomena, or terms which are defined solely by such descriptions. In like manner, the phenomenon determines the cause in a particular degree, and in another; and we have no immediate measure of the degree of the cause but the phenomenon itself. We take many measures of the cause, it is true; but on examination they will be found not to be immediate measures of the cause, but of the effect. Assuming gravitation as the cause of the planetary deviations from uniform rectilinear motion, we say that the gravitation of the moon is but $\frac{1}{3600}$th part of the gravitation of a stone thrown from the hand: but we say this only from observing that the deflection of the stone is 3600 times greater than the simultaneous deflection of the moon. In short, our whole knowledge of the cause is not only founded on our knowledge of the phenomenon, but it is the same. This will be found a remark of immense consequence in the prosecution of philosophical researches; and a strict attention to it will not only guard us against a thousand mistakes into which the reasoning pride of man would continually lead us, but will also enable us fully to detect many egregious and fatal blunders made in consequence of this philosophical vanity. Nothing can be more evident than that whenever we are puzzled, it would be folly to continue groping among those obscure beings called causes, when we have their prototypes, the phenomena themselves, in our hands.

Such is the account which may be given of philosophy, the study of the works of God, as related by causation. It is of vast extent, reaching from an atom to the glorious Author of the Universe, and contemplating the whole connected chain of intelligent, sensitive, and inanimate beings. The philosopher makes use of the descriptions and arrangements of the natural historian as of mighty use to himself in the beginning of his career, confiding in the uniformity of nature, and expecting that similarity in the quiescent properties of things will be accompanied by some resemblances in those more important properties which constitute their mutual dependencies, linking them together in a great and endlessly ramified chain of events.

We have endeavoured to ascertain with precision the peculiar province of philosophy, both by means of its object and its mode of procedure. After this it will not require many words to point out the methods for prosecuting the study with expedition and with success. The rules of philosophizing, which Newton premises to his account of the planetary motions, which he so scrupulously followed, and with a success which gives them great authority, are all in strict conformity to the view we have now given of the subject.

The chief rule is, that similar causes are to be assigned to similar phenomena. This is indeed the source of all our knowledge of connected nature; and without it the universe would only present to us an incomprehensible chaos. It is by no means, however, necessary to enjoin this as a maxim for our procedure: it is an instinctive propensity of the human mind. It is absolutely necessary, on the contrary, to caution us in the application of this propensity. We must be extremely confident in the certainty of the resemblance before we venture to make any inference. We are prone to reason from analogy: the very employment is agreeable; and we are ever disposed to embrace opportunities of engaging in it. For this reason we are satisfied with very slight resemblances, and eagerly run over the consequences, as if the resemblance were complete; and our researches frequently terminate in falsehood.

This propensity to analogical reasoning is aided by another equally strong, and equally useful, when properly directed; we mean the propensity to form general laws: it is in fact a propensity to discover causes, which is equivalent to the establishing of general laws. It appears in another form, and is called a love of or taste for simplicity; and this is encouraged or justified as agreeable to the uniformity and simplicity of nature. "Natura semper sibi similis et consona," says Newton; "Frustra fit per plura, quo fieri potest per pauciora," says another. The beautiful, the wise economy of nature, are phrases in every body's mouth; and Newton enjoins us to adopt no more causes than are sufficient to explain explain the phenomena. All this is very well, and is true in its own degree; but it is too frequently the subterfuge of human vanity and self-love. This inordinate admiration of the economy and simplicity of nature is generally conjoined with a manifest love of system, and with the actual production of some new system, where from one general principle some extensive theory or explanation is deduced and offered to the world. The author sees a sort of resemblance between a certain series of phenomena and the consequences of some principle, and thinks the principle adequate to their explanation. Then, on the authority of the acknowledged simplicity of nature, he roundly excludes all other principles of explanation; because, says he, this principle is sufficient, "et frustra fit per plura," &c. We could point out many instances of this kind in the writings of perhaps the first mathematician and the poorest philosopher of this century; where extensive theories are thus cavalierly exhibited, which a few years examination have shown to be nothing but analogies, indistinctly observed, and, what is worse, inaccurately applied.

To regulate these hazardous propensities, and keep philosophers in the right path, Newton inculcates another rule, or rather gives a modification of this injunction of simplicity. He enjoins that no cause shall be admitted but what is real. His words are, that no causes shall be admitted but such as are true, and sufficient to account for the phenomena. We apprehend that the meaning of this rule has been mistaken by many philosophers, who imagine that by true he means causes which really exist in nature, and are not mere creatures of the imagination. We have met with some who would boggle at the doctrines of Aristotle respecting the planetary motions, viz. that they are carried along by conducting intelligent minds, because we know of none such in the universe; and who would nevertheless think the doctrine of the Cartesian vortices deserving of at least an examination, because we see such vortices exist, and produce effects which have some resemblance to the planetary motions, and have justly rejected them, solely because this resemblance has been very imperfect. We apprehend Newton's meaning by these words is, that no cause of any event shall be admitted, or even considered, which we do not know to be actually concurring or exerting some influence in that very event. If this be his meaning, he would reject the Cartesian vortices, and the conducting spirits of Aristotle, for one and the same reason; not because they were not adequate to the explanation, nor because such causes do not exist in nature, but because we did not see them anyhow concerned in the phenomenon under consideration. We neither see a spirit nor a vortex, and therefore need not trouble ourselves with enquiring what effects they would produce. Now we know that this was his very conduct, and what has distinguished him from all philosophers who preceded him, though many, by following his example, have also been rewarded by similar success. This has procured to Newton the character of the modest philosopher; and modest his procedure may, for distinction's sake, be called, because the contrary procedure of others did not originate so much from ignorance as from vanity. Newton's conductor in this was not modesty, but sagacity, prudence, caution, and to say it purely, it was sound judgment.

For the bonds of nature, the supposed philosophical causes are not observed; they are inferred from the phenomena. When two substances are observed, and only when they are observed, to be connected in any series of events, we infer that they are connected by a natural power; but when one of the substances is not seen, but fancied, no law of human thought produces any inference whatever. For this reason alone Newton stopped short at the last fact which he could discover in the solar system, that all bodies were deflected to all other bodies, according to certain regulations of distance and quantity of matter. When told that he had done nothing in philosophy, that he had discovered no cause, and that to merit any praise he must show how this deflection was produced—he said that he knew no more than he had told them; that he saw nothing causing this deflection; and was contented with having discovered it so exactly, that a good mathematician could now make tables of the planetary motions as accurate as he pleased, and with hoping in a few years to have every purpose of navigation and of philosophical curiosity completely answered; and he was not disappointed. And when philosophers on all sides were contriving hypothetical fluids and vortices which would produce these deflections, he contented himself with showing the total inconsistency of these explanations with the mechanical principles acknowledged by their authors; showing that they had transgressed both parts of his rule, their causes neither being real nor sufficient for explaining the phenomena. A cause is sufficient for explaining a phenomenon only when its legitimate consequences are perfectly agreeable to these phenomena.

Newton's discoveries remain without any diminution or change: no philosopher has yet advanced a step further.

But let not the authority, or even the success, of this doctrine be our guide. Is his rule founded in reason? It surely is. For if philosophy be the only interpretation of nature's language, the inference of causes from phenomena, a fancied or hypothetical phenomenon can produce nothing but a fanciful cause, and can make no addition to our knowledge of real nature.

All hypotheses therefore must be banished from philosophical discussion as frivolous and useless, administering to vanity alone. As the explanation of any appearance is nothing but the pointing out the general fact, of which this is a particular instance, a hypothesis can give no explanation: knowing nothing of cause and effect but the conjunction of two events, we see nothing of causation where one of the events is hypothetical. Although all the legitimate consequences of a hypothetical principle should be perfectly similar to the phenomenon, it is extremely dangerous to assume this principle as the real cause. It is illogical to make use of the economy of nature as an argument for the truth of any hypothesis: for if true, it is a physical truth, a matter of fact, and true only to the extent in which it is observed, and we are not entitled to say that it is so one step farther; therefore not in this case till it be observed. But the proposition that nature is so economical is false; and it is astonishing that it has been so lazily acquiesced in by the readers of hypotheses: for it is not the authors who are deceived by it, they are generally led by their own vanity. Nothing is more observable than the prodigious variety of nature. That the same phenomena may be produced by different means is well known to the astronomers. nomers, who must all grant, that the appearances of motion will be precisely the same whether the earth moves round the sun like the other planets, or whether the sun with his attendant planets moves round the earth; and that the demonstration of the first opinion is had from a fact totally unconnected with all the deflections or even with their causes: for it may be asserted, that Dr Bradley's discovery of the aberration of the fixed stars, in consequence of the progressive motion of light, was the first thing which put the Copernican system beyond question; and even this is still capable of being explained in another way. The Author of Nature seems to delight in variety; and there cannot be named a single purpose on which the most inconceivable fertility in resource is not observed. It is the most delightful occupation of the curious mind and the sensible heart to contemplate the various contrivances of nature in accomplishing similar ends.

As a principle therefore on which to found any maxim of philosophical procedure, this is not only injudicious, because imprudent and apt to mislead, but as false, and almost sure to mislead. In conformity to this observation, it must be added, that nothing has done so much harm in philosophy as the introduction of hypotheses.

Authors have commonly been satisfied with very slight resemblances, and readers are easily misled by the appearances of reasoning which these resemblances have countenanced. The ancients, and above all Aristotle, were much given to this mode of explanation, and have filled philosophy with absurdities. The slightest resemblances were with them sufficient foundations of theories. It has been by very slow degrees that men have learned caution in this respect; and we are sorry to say that we are not yet cured of the disease of hypothetical systematizing, and to see attempts made by ingenious men to bring the frivolous theories of antiquity again into credit. Nay, modern philosophers even of the greatest name are by no means exempted from the reproach of hypothetical theories. Their writings abound in ethers, nervous fluids, animal spirits, vortices, vibrations, and other invisible agents. We may affirm that all these attempts may be shown to be either unintelligible, fruitless, or false. Either the hypothesis has been such that no consequence can be distinctly drawn from it, on account of its obscurity and total want of resemblance to anything we know; or the just and legitimate consequences of the hypothesis are inconsistent with the phenomena (N). This is remarkably the case in the hypotheses which have been introduced for the explanation of the mechanical phenomena of the universe. These can be examined by accurate science, and the consequences compared without any mistake; and nothing else but a perfect agreement should induce us even to listen to any hypothesis whatever.

It may here be asked, Whether, in the case of the most perfect agreement, after the most extensive comparison, the hypothesis should be admitted? We believe that this must be left to the feelings of the mind. When the belief is irresistible, we can reason no more. But as there is no impossibility of as perfect an agreement with some other hypothesis, it is evident that it does not convey an irrefragable title to our hypothesis. It is said, that such an agreement authorises the reception of the hypothetical theory in the same manner as we must admit that to be the true cypher of a letter which will make perfect sense of it. But this is not true: in deciphering a letter we know the sounds which must be represented by the characters, and that they are really the constituents of speech; but in hypothetical explanations the first principle is not known to exist; nay, it is possible to make two cyphers, each of which shall give a meaning to the letter. Instances of this are to be seen in treatises on the art of deciphering; and there has been lately discovered a national character (the ogam discovered in Ireland) which has this property.

We conclude our criticism on hypothetical explanations with this observation, that it is impossible that they can give any addition of knowledge. In every hypothesis we thrust in an intermediate event between the phenomenon and some general law; and this event is not seen, but supposed. Therefore, according to the true maxims of philosophical investigation, we give no explanation; for we are not by this means enabled to assign the general law in which this particular phenomenon is included; nay, the hypothesis makes no addition to our list of general laws; for our hypotheses must be selected, in order to tally with all the phenomena. The hypothesis therefore is understood only by and in the phenomena; and it must not be made more general than the phenomena themselves. The hypothesis gives no generalisation of facts. Its very application is founded on a great coincidence of facts; and the hypothetical fact is thrust in between two which we really observe to be united by nature. The applicability therefore of the hypothesis

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(N) It has often been matter of amusement to us to examine the hypothetical theories of ingenious men, and to observe the power of nature even when we are transgressing her commands, Naturam expellat furca, tumen usque revertitur. The hypothesis of an ingenious man is framed in perfect conformity to nature's dictates; for you will find that the hypothetical cause is touched and retouched, like the first sitting of a picture, till it is made to resemble the phenomena, and the cause is still inferred, nay explained, in spite of all his ingenuity, from the phenomenon; and then, instead of desiring the spectators to pay him his due praise, by saying that the picture is like the man, he insists that they shall say, what gives him no credit, that the man is like the picture. But alas! this is seldom the case: The picture is generally an anamorphosis, unlike any thing extant in nature, and having parts totally incongruous. We have seen such pictures, where a wood is standing on the sea, and an eye is on the end of an elephant's trunk; and yet when this was viewed through a proper glass, the wood became an eyebrow to the eye, and the proboscis was a very pretty ringlet of hair. We beg indulgence for this piece of levity, because it is a most apposite illustration of a hypothetical theory. The resemblance between the principle and phenomenon is true only in detached unconnected scraps, and the principle itself is an incongruous patchwork. But by a perversion of the rules of logic, all these inconsistencies are put out of view, and the explanation is something like the phenomenon. View of hypothesis is not more extensive than the similarity of facts which we observe, and the hypothetical law is not more general than the observed law. Let us then throw away entirely the hypothetical law, and insert the observed one in our list of general laws; it will be in different language from the hypothetical law, but it will express the same facts in nature.

It is in experimental philosophy alone that hypotheses can have any just claim to admission; and here they are not admitted as explanations, but as conjectures serving to direct our line of experiments.

Effects only appear; and by their appearance, and the previous information of experience, causes are immediately ascertained by the perfect similarity of the whole train of events to other trains formerly observed: Or they are suggested by more imperfect resemblances of the phenomena; and these suggestions are made with stronger or fainter evidence, according as the resemblance is more or less perfect. These suggestions do not amount to a confidential inference, and only raise a conjecture. Wishing to verify or overturn this conjecture, we have recourse to experiment; and we put the subject under consideration in such a situation, that we can say what will be the effect of the conjectural cause if real. If this tallies with the appearance, our conjecture has more probability of truth, and we vary the situation, which will produce a new set of effects of the conjectured cause, and so on. It is evident that the probability of our conjecture will increase with the increase of the conformity of the legitimate effects of the supposed cause with the phenomena, and that it will be entirely destroyed by one disagreement. In this way conjectures have their great use, and are the ordinary means by which experimental philosophy is improved. But conjectural systems are worse than nonsense, filling the mind with false notions of nature, and generally leading us into a course of improper conduct when they become principles of action. This is acknowledged even by the abettors of hypothetical systems themselves when employed in overturning those of their predecessors; and establishing their own: witness the successive maintainers of the many hypothetical systems in medicine, which have had their short-lived course within these two last centuries.

Let every person therefore who calls himself a philosopher resolutely determine to reject all temptations to this kind of system-making, and let him never consider any composition of this kind as anything better than the amusement of an idle hour.

After these observations, it cannot require much discussion to mark the mode of procedure which will insure progress in all philosophical investigations.

The sphere of our intuitive knowledge is very limited; and we must be indebted for the greatest part of our intellectual attainments to our rational powers, and it must be deductive. In the spontaneous phenomena of nature, whether of mind or body, it seldom happens that the energy of that natural power, which is the principle of explanation, is so immediately connected with the phenomenon that we see the connection at once. Its exertions are frequently concealed, and in all cases modified, by the joint exertions of other natural powers: the particular exertion of each must be considered apart, and their mutual connection traced out. It is only in this way that we can discover the perhaps long train of intermediate operations, and also see in what manner and degree the real principle of explanation concurs in the ostensible process of nature.

In all such cases it is evident that our investigation (and investigation it most strictly is) must proceed by steps, conducted by the sure hand of logical method. To take an instance from the material world, let us listen to Galileo while he is teaching his friends the cause of the rise of water in a pump. He says that it is owing to the pressure of the air. This is his principle; and he announces it in all its extent. All matter, says he, is heavy, and in particular air is heavy. He then points out the connection of this general principle with the phenomenon. Air being heavy, it must be supported; it must lie and press on what supports it; it must press on the surface AB of the water in the cistern surrounding the pipe CD of the pump; and also on the water C within this pipe. He then takes notice of another general principle which exerts its subordinate influence in this process. Water is a fluid; a fluid is a body whose parts yield to the smallest impression; and, by yielding, are easily moved among themselves; and no little parcel of the fluid can remain at rest unless it be equally pressed in every direction, but will recede from that side where it sustains the greatest pressure. In consequence of this fluidity, known to be a property of water, if any part of it is pressed, the pressure is propagated through the whole; and if not resisted on every side, the water will move to that side where the propagated pressure is not resisted. All these subordinate or collateral propositions are supposed to be previously demonstrated or allowed. Water therefore must yield to the pressure of the air unless pressed by it on every side, and must move to that side where it is not withheld by some opposite pressure. He then proceeds to show, from the structure of the pump, that there is no opposing pressure on the water in the inside of the pump. "For (says he) suppose the piston thrust down till it touches the surface of the water in the pipe; suppose the piston now drawn up by a power sufficient to lift it, and all the air incumbent on it; and suppose it drawn up a foot or fathom—there remains nothing now (says he) that I know of, to press on the surface of the water. In short (says he), gentlemen, it appears to me, that the water in the pump is in the same situation that it would be if there were no air at all, but water poured into the cistern to a height AF: such, that the column of water FABG presses on the surface AB as much as the air does. Now in this case we know that the water at C is pressed upwards..." wards with a force equal to the weight of a column of water, having the section of the pipe for its base and CH for its height. The water below C therefore will be pressed up into the pipe CD, and will rise to G, so that it is on a level with the external water FG; that is, it will rise to H. This is a necessary consequence of the weight and pressure of the incumbent column FABG, and the fluidity of the water in the cistern. Consequences perfectly similar must necessarily follow from the weight and pressure of the air; and therefore on drawing up the piston from the surface C of the water, with which it was in contact, the water must follow it till it attain that height which will make its own weight a balance for the pressure of the circumambient air. Accordingly, gentlemen, the Italian plumbers inform me, that a pump will not raise water quite fifty palms; and from their information I conclude, that a pillar of water-fifty palms high is somewhat heavier than a pillar of air of the same base, and reaching to the top of the atmosphere."

Thus is the phenomenon explained. The rise of the water in the pump is shown to be a particular case of the general fact in hydrostatics, that fluids in communicating vessels will stand at heights which are inversely as their densities, or that columns of equal weights are in equilibrio.

This way of proceeding is called arguing *a priori*, the synthetic method. It is founded on just principles; and the great progress which we have made in the mathematical sciences by this mode of reasoning shows to what length it may be carried with irresistible evidence. It has long been considered as the only inlet to true knowledge; and nothing was allowed to be known with certainty which could not be demonstrated in this way to be true. Accordingly logic, or the art of reasoning, which was also called the art of discovering truth, was nothing but a set of rules for successfully conducting this mode of argument.

Under the direction of this infallible guide, it is not surely unreasonable to expect that philosophy has made sure progress towards perfection; and as we know that the brightest geniuses of Athens and of Rome were for ages solely occupied in philosophical researches in every path of human knowledge, it is equally reasonable to suppose that the progress has not only been sure but great. We have seen that the explanation of an appearance in nature is nothing but the arrangement of it into that general class in which it is comprehended. The class has its distinguishing mark, which, when it is found in the phenomenon under consideration, fixes it in its class, there to remain for ever an addition to our stock of knowledge. Nothing can be lost any other way but by forgetting it; and the doctrines of philosophers must be stable like the laws of nature.

We have seen, however, that the very reverse of all this is the case; that philosophy has but very lately emerged from worse than total darkness and ignorance; that what passed under the name of philosophy was nothing but systems of errors (if systems they could be called), which were termed doctrines, delivered with the most imposing apparatus of logical demonstration, but belied in almost every instance by experience, and affording us no assistance in the application of the powers of nature to the purposes of life. Nor will this excite much wonder in the mind of the enlightened reader of the present day, who reflects on the use that in this dialectic process was made of the categories, and the method in which those categories were formed. From first principles so vague in themselves, and so gratuitously assumed, ingenious men might deduce many different conclusions all equally erroneous; and that this was actually done, no surer evidence can be given, than that hardly a lifetime elapsed in which the whole system of doctrines which had captivated the minds of the most penetrating, have been oftener than once exploded and overturned by another system, which flourished for a while, and then was supplanted by a third which shared the same fate. Here was an infallible proof of their error, for instability is incompatible with truth.

It is allowed by all that this has been the case in those branches of study at least which contemplate the philosophical relations of the material world, in astronomy, in mechanical philosophy, in chemistry, in physiology, in medicine, in agriculture. It is also acknowledged, that in the course of less than two centuries back we have acquired much knowledge on these very subjects, call it philosophy, or by what name you will, so much more conformable to the natural course of things, that the deductions made from it by the same rules of the synthetic method are more conformable to fact, and therefore better fitted to direct our conduct and improve our powers. It is also certain that these bodies of doctrine which go by the name of philosophical systems, have much more stability than in ancient times; and though sometimes in part superseded, are seldom or never wholly exploded.

This cannot perhaps be affirmed with equal confidence with respect to these speculations which have our intellect or propensities for their object: and we have not perhaps attained such a representation of human nature as will bear comparison with the original; nor will the legitimate deductions from such doctrines be of much more service to us for directing our conduct than those of ancient times: and while we observe this difference between these two general classes of speculations, we may remark, that it is conjoined with a difference in the manner of conducting the study. We have proceeded in the old Aristotelian method when investigating the nature of mind; but we see the material philosophers running about, passing much of their time away from books in the shop of the artizan, or in the open fields engaged in observation, labouring with their hands, and busy with experiments. But the speculative on the intellect and the active powers of the human soul seems unwilling to be indebted to any thing but his own ingenuity, and his labours are confined to the closet. In the first class, we have met with something like success, and we have improved many arts: in the other, No it is to be feared that we are not much wiser, or better, trath or happier, for all our philosophic attainments.

Here, therefore, must surely have been some great, some fatal mistake. There has indeed been a material defect in our mode of procedure, in the employment of this method of reasoning as an inlet to truth. The fact is, that philosophers have totally mistaken the road of discovery, and have pretended to set out in their investigation from the very point where this journey should have terminated.

The Aristotelian logic, the syllogistic art, that art so much boasted of as the only inlet to true knowledge, the only means of discovery, is in direct opposition to the ordinary procedure of nature, by which we every day, and in every action of our lives, acquire knowledge and discover truth. It is not the art of discovering truth, it is the art of communicating knowledge, and of detecting error: it is nothing more than the application of this maxim, 'whatever is true of a whole class of objects, is true of each individual of that class.'

This is not a just account of the art of discovering truth, nor is it a complete account of the art of reasoning. Reasoning is the producing belief; and whatever mode of argumentation invariably and irresistibly produces belief, is reasoning. The ancient logic supposes that all the first principles are already known, and that nothing is wanted but the application of them to particular facts. But were this true, the application of them, as we have already observed, can hardly be called a discovery; but it is not true; and the fact is, that the first principles are generally the chief objects of our research, and that they have come into view only now and then as it were by accident, and never by the labour of the logician. He indeed can tell us whether we have been mistaken; for, if our general principle be true, it must influence every particular case. If, therefore, it be false in any one of these, it is not a true principle. And it is here that we discover the source of that fluctuation which is so much complained of in philosophy. The authors of systems give a set of consecutive propositions logically deduced from a first principle, which has been hastily adopted, and has no foundation in nature. This does not hinder the amusement of framing a system from it, nor this system from pleasing by its symmetry; and it takes a run: but when some officious follower thinks of making some use of it, which requires the comparison with experience and observation, they are found totally unlike, and the whole fabric must be abandoned as unsound; and thus the successive systems were continually pushing out their predecessors, and presently met with the same treatment.

How was this to be remedied? The ratiocination was seldom egregiously wrong; the syllogistic art had ere now attained a degree of perfection which left little room for improvement, and was so familiarly understood by the philosophical practitioners, that they seldom committed any great blunders. Must we examine the first principles? This was a task quite new in science; and there were hardly any rules in the received systems of logic to direct us to the successful performance of it. Aristotle, the sagacious inventor of those rules, had not totally omitted it; but in the fervour of philosophic speculation he had made little use of them. His fertile genius never was at a loss for first principles, which answered the purpose of verbal disquisition without much risk of being belied on account of its dissimilitude to nature; for there was frequently no prototype with which his systematic doctrine could be compared. His enthusiastic followers found abundant amusement in following his example; and philosophy, no longer in the hands of men acquainted with the world, conversant in the great book of nature, was now confined almost entirely to recluse monks, equally ignorant of men and of things.

But curiosity was awakened, and the men of genius were fretted as well as disgusted with the disquisitions of the schools, which one moment raised expectations by the symmetry of composition, and the next moment blasted them by their inconsistency with experience.

They saw that the best way was to begin de novo, to throw away the first principles altogether, without exception or examination, and endeavour to find out new ones, which should stand the test of logic; that is, should in every case be agreeable to fact.

Philosophers began to reflect, that under the unnoticed tuition of kind nature we have acquired much useful knowledge. It is therefore highly probable, that her method is the most proper for acquiring knowledge, and that by imitating her manner we shall have the like success. We are too apt to slight the occupations of children, whom we may observe continually busy turning everything over and over, putting them into every situation, and at every distance. We excuse it, saying that it is an innocent amusement; but we should say with an ingenious philosopher (Dr Reid), that they are most seriously and rationally employed: they are acquiring the habits of observation; and by merely indulging an undetermined curiosity, they are making themselves acquainted with surrounding objects: they are struck by similitudes, and amused with mere classification. If some new effect occurs from any of their little plays, they are eager to repeat it. When a child has for the first time tumbled a spoon from the table, and is pleased with its jingling noise on the floor, if another lie within its reach, it is sure to share the same fate. If the child be indulged in this diversion, it will repeat it with greediness that deserves our attention. The very first eager repetition shows a confidence in the constancy of natural operations, which we can hardly ascribe wholly to experience; and its keenness to repeat the experiment, shows the interest which it takes in the exercise of this most useful propensity. It is beginning the study of nature; and its occupation is the same with that of a Newton computing the motions of the moon by his sublime theory, and comparing his calculus with observation. The child and the philosopher are equally employed in the contemplation of a similarity of event, and are anxious that this similarity shall return. The child, it is true, thinks not of this abstract object of contemplation, but throws down the spoon again to have the pleasure of hearing it jingle. The philosopher suspects that the conjunction of events is the consequence of a general law of nature, and tries an experiment where this conjunction recurs. The child is happy, and eager to enjoy a pleasure which to us appears highly frivolous; but it has the same foundation with the pleasure of the philosopher, who rejoices in the success of his experiment: and the fact, formerly a trifle to both, now acquires importance. Both go on repeating the experiment, till the fact ceases to be a novelty to either: the child is satisfied, and the philosopher has now established a new law of nature.

Such (says this amiable philosopher) is the education of kind nature, who from the beginning to the end of our lives makes the play of her scholars their most instructive lessons, and has implanted in our mind the curiosity and the inductive propensity by which we are enabled and disposed to learn them. The exercise of this inductive principle, by which nature prompts us to infer general laws from the observation of particular facts, gives us a species of logic new in the schools, but old... It is a just and rational logic; for it is founded on, and indeed is only the habitual application of, this maxim, "That whatever is true with respect to every individual of a class of events, is true of the whole class." This is just the inverse of the maxim on which the Aristotelian logic wholly proceeds, and is of equal authority in the court of reason. Indeed the expression of the general law is only the abbreviated expression of every particular instance.

This new logic, therefore, or the logic of induction, must not be considered as subordinate to the old, or founded on it. See Logic, Part III. chap. 5. In fact, the use and legitimacy of the Aristotelian logic is founded on the inductive,

All animals are mortal; All men are animals; therefore All men are mortal.

This is no argument to any person who chooses to deny the mortality of man; even although he acknowledges his animal nature, he will deny the major proposition.

It is beside our purpose to show, how a point so general, so congenial to man, and so familiar, remained so long unnoticed, although the disquisition is curious and satisfactory. It was not till within these two centuries that the increasing demand for practical knowledge, particularly in the arts, made inquisitive men see how useless and insufficient was the learning of the schools in any road of investigation which was connected with life and business; and observe that society had received useful information chiefly from persons actually engaged in the arts which the speculists were endeavouring to illustrate; and that this knowledge consisted chiefly of experiments and observations, the only contributions which their authors could make to science.

The Novum Organum of Bacon, which points out the true method of forming a body of real and useful knowledge, namely, the study of nature in the way of description, observation, and experiment, is undoubtedly the noblest present that science ever received. It may be considered as the grammar of nature's language, and is a counter-part to the logic of Aristotle; not exploding it, but making it effectual.

As the logic of Aristotle had its rules, so has the Baconian or inductive; and this work, the Novum Organum Scientiarum, contains them all. The chief rule, and indeed the rule from which all the rest are but derivations, is, that "the induction of particulars must be carried as far as the general affirmation which is deduced from them." If this be not attended to, the mind of man, which from his earliest years shows great eagerness in searching for first principles, will frequently ascribe to the operation of a general principle events which are merely accidental. Hence the popular belief in omens, palmistry, and all kinds of fortune-telling.

This rule must evidently give a new turn to the whole track of philosophical investigation. In order to discover first principles, we must make extensive and accurate observations, so as to have copious inductions of facts, that we may not be deceived as to the extent of the principle inferred from them. We must extend our acquaintance with the phenomena, paying a minute attention to what is going on all around us; and we must study nature, not shut up in our closet drawing the picture from our own fancy, but in the world, copying our lines from her own features.

To delineate human nature, we must see how men act. To give the philosophy of the material world, we must notice its phenomena.

This method of studying nature has been prosecuted during these two last centuries with great eagerness and success. Philosophers have been busy in making accurate observations of facts, and copious collections of them. Men of genius have discovered points of resemblance, from which they have been able to infer many general powers both of mind and body; and resemblances among these have suggested powers still more general.

By these efforts investigation became familiar; philosophers studied the rules of the art, and became more expert; hypotheses were banished, and nothing was admitted as a principle which was not inferred from the most copious induction. Conclusions from such principles became every day more conformable to experience. Mistakes sometimes happened; but recourse being had to more accurate observation or more copious induction, the mistakes were corrected. In the present study of nature, our steps are more slow, and receding and painful; our conclusions are more limited and modest, but our discoveries are more certain and progressive, and the results are more applicable to the purposes of life. This pre-eminence of modern philosophy over the ancient is seen in every path of inquiry. It was first remarkable in the study of the material world; and there it still continues to be most conspicuous. But it is no less to be seen in the later performances of philosophers in metaphysics, pneumatology, and ethics, where the mode of investigation by analysis and experiment has been greatly adopted; and we may add, that it is this juster view of the employment which has restored philosophers to the world, to society. They are no longer to be found only in the academies of the sophists and the cloisters of a convent, but in the discharge of public and private duty. A philosophic genius is a genius for observation as well as reflection, and he says, Homo sum, humani a me nihil alienum puto.

After saying so much on the nature of the employment, and the mode of procedure, it requires no deep penetration to perceive the value of the philosophical character. If there is a propensity in the human mind which distinguishes us from the inferior orders of sentient beings, without the least circumstance of interference, a propensity which alone may be taken for the characteristic of the species, and of which no trace is to be found in any other, it is disinterested intellectual curiosity, a love of discovery for its own sake, independent of all its advantages.

We think highly (and with great justice do we think so) of our rational powers; but we may carry this too far, as we do every ground of self-estimation. To every man who enjoys the cheering thought of living under the care of a wise Creator, this boasted prerogative will be viewed with more modesty and diffidence; and He has given us evident marks of the rank in which He esteems the rational powers of man. In no case that is of essential importance, of indispensable necessity, not on ly To guide the helm, while passion blows the gale.

God has not trusted either the preservation of the individual or the continuance of the race to man's notions of the importance of the task, but has committed them to the surer guards of hunger and of sexual desire. In like manner, He has not left the improvement of his noblest work, the intellectual powers of the soul of man, to his own notions how important it is to his comfort that he be thoroughly acquainted with the objects around him. No: He has committed this also to the sure hand of curiosity: and He has made this so strong in a few superior souls, whom He has appointed to give light and knowledge to the whole species, as to abstract them from all other pursuits, and to engage them in intellectual research with an ardour which no attainment can ever quench, but, on the contrary, inflames it the more by every draught of knowledge.

But what need words

To paint its power? For this the daring youth Breaks from his weeping mother's folding arms In foreign climes to rove. The pensive sage, Headless of sleep, or midnight's hurtful vapour, Hangs o'er the sickly taper.—Hence the scorn Of all familiar prospects, though beheld With transport once. Hence the attentive gaze Of young astonishment.

Such is the bounteous providence of Heaven, In every breast implanting the desire Of objects new and strange, to urge us on With unremitting labour to attain The sacred stores that wait the rip'ning soul In Truth's exhaustless bosom. Aikenside.

But human life is not a situation of continual necessity; this would ill suit the plans of its beneficent Author: and it is from induction of phenomena totally opposite to this, and from such induction alone, that we have ever thought of a wise Creator. His wisdom appears only in His beneficence. Human life is a scene filled with enjoyment; and the soul of man is stored with propensities and powers which have pleasure, in direct terms, for their object. Another striking distinction of our nature is a continual disposition to refinement, of which few traces are to be found in the actions of other animals. There is hardly a gift of nature so grateful in itself as to please the freakish mind of man, till he has moulded it to his fancy. Not contented with food, with raiment, and with shelter, he must have nice cookery, ornamental dress, and elegant houses. He hunts when he is not hungry, and he refines sexual appetite into a most elegant passion. In like manner he has improved this anxious desire of the knowledge of the objects around him, so as to derive from them the means of subsistence and comfort, into the most elegant and pleasing of all gratifications, the accumulation of intellectual knowledge, independent of all consideration of its advantages. And as every man has a title to the enjoyment of such pleasures as he can attain without injuring his neighbour; so it is allowable to such as have got the means of intellectual improvement, without relinquishing the indispensable social duties, to push this advantage as far as it will go: and, in all ages and countries, it has been considered as forming the greatest distinction between men of easy fortune and the poor, who must earn their subsistence by the sweat of their brow. The plebeian must learn to work, the gentleman must learn to think; and nothing can be a surer mark of groveling soul than for a man of fortune to have an uncultivated mind.

Let us then cherish to the utmost this distinguishing propensity of the human soul: but let us do even this like philosophers. Let us cultivate it as it is: as the it is subject-handmaid to the arts and duties of life; as the guide vinct to something yet more excellent. A character is not to be estimated from what the person knows, but from what he can perform. The accumulation of intellectual knowledge is too apt to create an inordinate appetite for it: and the man habituated to speculation is, like the miser, too apt to place that pleasure in the mere possession, which he ought to look for only or chiefly in the judicious use of his favourite object. Like the miser, too, his habits of hoarding up generally unfit him for the very enjoyment which at setting out he proposed to himself. Seldom do we find the man, who has devoted his life to scientific pursuits for their own sake, possessed of that superiority of mind which the active employ to good purpose in times of perplexity; and much seldomer do we find him possessed of that promptitude of apprehension, and that decision of purpose, which are necessary for passing through the difficult scenes of human life.

But we may use the good things of this life without abusing them; and by moderation here, as in all other pursuits, derive those solid advantages which philosophy is able to bestow. And these advantages are great. To enumerate and describe them would be to write a great volume. We may just take notice of one, which is an obvious consequence of that strict and simple view which we have given of the subject; and this is a modest opinion of our attainments. Appearances are all limits of that we know; causes are for ever hid from our view; the powers of our nature do not lead us so far. Let us therefore, without hesitation, relinquish all pursuits which have such things as ultimate principles for objects of examination. Let us attend to the subordinations of things which it is our great business to explore. Among these there is such a subordination as that of means to ends, and of instruments to an operation. All will acknowledge the absurdity of the project of viewing light with a microscope. It is equally absurd for us to examine the nature of knowledge, of truth, of infinite wisdom, by our intellectual powers. We have a wide field of accessible knowledge in the works of God; and one of the greatest advantages, and of the most sublime pleasures, which we can derive from the contemplation, is the view which a judicious philosophical research will most infallibly give us of a world, not consisting of a number of detached objects, connected only by the fleeting tie of coexistence, but an universe, a system of beings, all connected together by causation, with innumerable degrees of subordination and sub-serviency, and all cooperating in the production of one great and glorious purpose. The heart which has but a spark of sensibility must be warned by such a prospect, must be pleased to find itself an important part of this stupendous machine; and cannot but adore the incomprehensible Artist. View of tist who contrived, created, and directs the whole. Let Bacon's us not listen, then, to the timid admonitions of theological ignorance, which shrinks with superstitions horror from the thoughts of accounting for every thing by the powers of nature, and considers these attempts as an apologetic disquisition to atheism. Philosophical disquisition will, on the contrary, exhibit these general laws of the universe, just notions that wonderful concatenation and adjustment of every of our own thing both material and intellectual, as the most striking instance of incomprehensible wisdom; which, by means so few and so simple, can produce effects which by their grandeur dazzle our imagination, and by their multiplicity elude all possibility of enumeration. Of all the obstacles which the weakness, the folly, or the sinful vanity of men, has thrown in the way of the theologian, there is none so fatal, so hostile to all his endeavours, as a cold and comfortless system of materialism, which the reasoning pride of man first engendered, which made a figure among a few speculativeists in the last century, but was soon forgotten by the philosophers really busy with the observation of nature and of nature's God. It has of late reared up its head, being now cherished by all who wish to get rid of the stings of remorse, as the only opinion compatible with the peace of the licentious and the sensual; for we may say to them as Henry IV. said to the prince of Wales, "Thy wish was father, Harry, to that thought." In Bacon's vain will the divine attempt to lay this devil with the metaphysical exorcisms of the schools; it is philosophy alone that can detect the cheat. Philosophy singles out the characteristic phenomena which distinguish every substance; and philosophy never will hesitate in saying that there is a set of phenomena which characterise mind and another which characterise body, and that these are toto ceelo different. Continually appealing to fact, to the phenomena, for our knowledge of every cause, we shall have no difficulty in deciding that thought, memory, volition, joy, hope, are not compatible attributes with bulk, weight, elasticity, fluidity. Tuta sub agide Pallas; philosophy will maintain the dignity of human nature, will detect the sophisms of the materialists, confute their arguments; and she alone will restore to the countenance of nature that ineffable beauty, of which those would deprive her, who would take away the supreme Mind which shines from within, and gives life and expression to every feature.

For a view of the progress of modern philosophy, see the Dissertations prefixed to the volumes of the Supplement.

**PHI**

Philosophy

Natural Philosophy. See Natural Philosophy,

Philosophy, and Physics.

Experimental Philosophy. See Experimental Philosophy.

Moral Philosophy. See Moral Philosophy.