(from the Greek, \textit{scena scene}, and \textit{graph} description), in perspective, a representation of a body on a perspective plane; or a description thereof in all its dimensions, such as it appears to the eye. See PERSPECTIVE.

SCETIC, \textit{σκεπτικός}, from \textit{σκεπτομαι}, "I consider, look about, or deliberate," properly signifies considera- A system of philosophy thus founded on doubt, and clouded with uncertainty, could neither teach tenets of any importance, nor prescribe a certain rule of conduct; and accordingly we find that the followers of skepticism were guided entirely by chance. As they could form no certain judgement respecting good and evil, they accidentally learned the folly of eagerly pursuing any apparent good, or of avoiding any apparent evil; and their minds of course settled into a state of undisturbed tranquillity, the grand postulatum of their system.

In the schools of the sceptics we find ten distinct topics of argument urged in support of the doctrine of uncertainty, with this precaution, however, that nothing could be positively affirmed either concerning their number or their force. These arguments chiefly respect objects of sense: they place all knowledge in appearance; and, as the same things appear very different to different people, it is impossible to say which appearance most truly expresses their real nature. They likewise say, that our judgement is liable to uncertainty from the circumstance of frequent or rare occurrence, and that mankind are continually led into different conceptions concerning the same thing by means of custom, law, fabulous tales, and established opinions. On all these accounts they think every human judgement is liable to uncertainty; and concerning any thing they can only affirm, that it seems to be, not that it is what it seems.

This doubtful reasoning, if reasoning it may be called, the sceptics extended to all the sciences, in which they discovered nothing true, or which could be absolutely affirmed. In all nature, in physics, morals, and theology, they found contradictory opinions, and inexplicable or incomprehensible phenomena. In physics, the appearances they thought might be deceitful; and respecting the nature of God and the duties of morality, men were, in their opinion, equally ignorant and uncertain. To overturn the sophistical arguments of these sceptical reasoners would be no difficult matter, if their reasoning were worthy of confutation. Indeed, their great principle is sufficiently, though shortly refuted by Plato, in these words: "When you say all things are incomprehensible (says he), do you comprehend or conceive that they are thus incomprehensible, or do you not? If you do, then something is comprehensible; if you do not, there is no reason we should believe you, since you do not comprehend your own assertion."

But skepticism has not been confined entirely to the ancients and to the followers of Pyrrho. Numerous sceptics have arisen also in modern times, varying in their principles, manners, and character, as chance, prejudice, vanity, weakness, or indolence, prompted them. The great object, however, which they seem to have in view, is to overturn, or at least to weaken, the evidence of analogy, experience, and testimony; though some of them have even attempted to show, that the axioms of geometry are uncertain, and its demonstrations inconclusive. This last attempt has not indeed been often made; but the chief aim of Mr Hume's philosophical writings is to introduce doubt into every branch of physics, metaphysics, history, ethics, and theology. It is needless to give a specimen of his reasonings in support of modern skepticism. The most important of them have been noticed elsewhere (see Miracle, Metaphysics, and Philosophy, No. 41); and such of our readers as have any relish for speculations of that nature can be no strangers to his Essays, or to the able confutations of them by the Doctors Reid, Campbell, Gregory, and Beattie, who have likewise exposed the weaknesses of the sceptical reasonings of Descartes, Malbranche, and other philosophers of great fame in the same school.