MAN, the noblest of all earthly creatures, stands related, on the one hand, through his body, to the world of matter, and on the other, through his mind, to the world of spirit. For until it can be established inductively that the modes of extension and the modes of thought are alike ultimately referable, as some have alleged, to one common substance, the laws of a sound philosophy demand the ascription of the one class of phenomena to one substance termed matter, and of the other class of phenomena to another substance termed mind. With his sensuous nature binding him fast to the present world, and his moral and religious nature raising him towards God,—at the verge of the animal kingdom most remote from its point of contact with the kingdom of organic life, yet the occupant of that other kingdom of pure intelligence where the conscience asserts its authority and dispenses its awards,—man, the only representative of the order Bimana, the pipos, the voice-dividing, the creature of speech, and possessor of the higher reason, stands really where he was first placed—at the head of all earthly creatures, the sole lord of the creation. From this duality of man's nature there results the two-fold division of the human sciences into mental and physical. In the former we consider man as a being capable of knowing and doing; in the latter, as a portion of organized animal matter. The mental sciences are distributed into LOGIC, METAPHYSICS, LANGUAGE, MORAL PHILOSOPHY, and THEOLOGY. In LOGIC we study the laws of thought as thought; in METAPHYSICS we either study the faculties, operations, and laws of the mind, viz., Psychology, or inquire into the nature of being as distinguished from phenomenon, viz., Ontology; in LANGUAGE we view man as capable of speech, of forming articulate sounds expressive of his thoughts and feelings; in MORAL PHILOSOPHY, or Ethics, we regard him as a responsible agent, and inquire into the nature of human duty in all its relationships; in THEOLOGY and MYTHOLOGY, again, we deal with man as a creature endowed with a religious sense—as a being capable of worship. The physical sciences which refer directly to man are ETHNOLOGY, ANATOMY, and PHYSIOLOGY. In the first we consider man as an object of natural history; in the second we investigate the structure of his body; and in the third we study the doctrine of its vital phenomena.
These branches of knowledge regard man chiefly in his normal condition. For the abnormal or diseased state of man's mind, see MENTAL DISEASES; and for the abnormal or diseased state of his body, see MEDICINE, &c.