IDEA (Gr. Ibia, connected with i&eiv, to see; cf.

See also:

• LAT

Lat.

See also:

• SPECIES

species from specere, to look at)  , a term used both popularly and in philosophical terminology with the general sense of " mental picture." To have no idea how a thing happened is to be without a mental picture of an occurrence . In this general sense it is synonymous with concept (q.v.) in its popular usage . In philosophy the term " idea " is common to all languages and periods, but there is scarcely any term which has been used with so many different shades of meaning . Plato used it in the sphere of metaphysics for the eternally existing reality, th( archetype, of which the objects of sense are more or less imperfect copies . Chairs may be of different forms, sizes, colours and so forth, but " laid up in the mind of God " there is the one permanent idea or type, of which the many physical chairs are derived with various degrees of imperfection . From this doctrine it follows that these ideas are the sole reality (see further IDEALISM) ; in opposition to it are the empirical thinkers of all time who find reality in particular physical objects (see HYLozoISM, EMPIRICISM, &c.) . In striking contrast to Plato's use is that of John Locke, who defines " idea "- as " whatever is the object of understanding when a man thinks " (Essay on the Human Understanding (I.), vi . 8) . Here the term is applied not to the mental process, but to anything whether physical or intellectual which is the object of it . Hume differs from Locke by limiting " idea " to the more or less vague mental reconstructions of perceptions, the perceptual process being described as an " impression." Wundt widens the term to include " conscious representation of some object or process of the external world." In so doing he includes not only ideas of memory and imagination, but also perceptual processes, whereas other psychologists confine the term to the first two groups . G . F .

Stout and J . M .

Baldwin, in the Dictionary of Philosophy and Psychology, i . 498, define " idea " as " the reproduction with a more or less adequate image, of an object not actually present to the senses." They point out that an idea and a perception are by various authorities contrasted in various or in any of the newer forms which seek for the ultimate essence ways . " Difference in degree of intensity," " comparative of both mind and matter in some unknown force or energy which, absence of bodily movement on the part of the subject," " corn- while in itself it is neither, yet contains the potentiality of both. parative dependence on mental activity," are suggested by It is true that in some modern developments of idealism the psychologists as characteristic of an idea as compared with a ultimate reality is conceived of in an impersonal way, but it is perception. usually added that this ultimate or absolute being is not some- It should be observed that an idea, in the narrower and thing lower but higher than self-conscious personality, including generally accepted sense of a mental reproduction, is frequently it as a more fully developed form may be said to include a more composite . That is, as in the example given above of the idea elementary . of chair, a great many objects, differing materially in detail, 2 . Origin and Development of Idealism.—In its self-conscious all call a single idea . When a man, for example, has obtained form idealism is a modern doctrine . In it the self or subject an idea of chairs in general by comparison with which he can may be said to have come to its rights . This was possible in say " This is a chair, that is a stool," he has what is known any complete sense only after the introspective movement as an " abstract idea " distinct from the reproduction in his represented by the middle ages had done its work, and the mind of any particular chair (see ABSTRACTION) . Furthermore thought of the individual mind and will as possessed of relative a complex idea may not have any corresponding physical independence had worked itself out into some degree of clearness. object, though its particular constituent elements may severally In this respect Descartes' dictum—cogito ergo sum—may be be the reproductions of actual perceptions .

Thus the idea of said to have struck the keynote of modern philosophy, and all a centaur is a complex mental picture composed of the subsequent

speculation to have been merely a prolonged corn-ideas of man and horse, that of a mermaid of a woman and a mentary upon it . While in its completer form it is thus a fish. doctrine distinctive of modern times, idealism has its roots far See PSYCHOLOGY. back in the history of thought .