IDEA,OLOGY. The philosophy of the human mind. We are conscious of our own existence ; and in this consciousness we perceive a certain variety or succes sive change, which we distinguish by the name of thought. It seems as if it would be a vain attempt to investigate by what physical operations the proceedings of the mind may be caused, supported, or go verned. The primary objects of thought are derived from our sensations or per ceptions. We can form no conception of any subject of thought, which shall not be referable to, the senses. During the ac tual time of sensation, we suppose our selves to be operated upon by some be. ings or objects which constitute no part of ourselves ; and we do not hesitate to infer from those sensations, that an ex ternal universe does actually subsist. Berkeley, Hume, and others, have made this a subject of question ; and it must be confessed, that we have 'no absolute proof respecting it. From the certainty, how ever, that we ourselves do not cause the changes which produce sensation in us, we are irresistibly impelled to an affirma tive decision of this question ; which after all seems neither important nor useful, more especially when we consider, that the same uncertainty pervades all our researches, whenever we refine so far as to treat of subjects which are not refera ble to cause and effect.
In many instances, the sensations we experience afford some resemblance of the objects which cause them, as in the figures of bodies ; but in others, it is pro bable that no such resemblance exists, as in colours, sounds, &c. A distinction has therefore very properly been made, be which is perceived, and the cause of the perception; and, moreover, as we find that effects, similar to our antecedent perceptions, may and do take place, though the organs of sense are not then acted upon, we make a further dis tinction between these last, and the per ceptions themselves. We call them They not only resemble the perceptions, as individually considered, but likewise make their appearance in the same ar rangement or order of recurrence. We
think we perform a positive act, in many instances, in bringing them forward, which we call an act of the memory, or recol lection; and their concomitant appear ance, or the succession of ideas by recol lection, in the similarity or the order of the sensations, has been called the asso ciation of ideas. The same term is like wise applied, when we speak of the re currence, in idea, of an entire contem poraneous sensation, in consequence of part of it being brought forward in the memory.
Much discussion has taken place among philosophers, respecting the origin and nature of our ideas ; in which it must be confessed, that a misapplication of terms, a confusion of intellectual research, with an admixture of theological notions, and several other causes, have united to ren der a plain subject considerably obscure, even in the hands of men of much talent and acuteness. In particular, it has been a subject of controversy whether man possesses innate ideas If an idea be the recollected picture of a sensation, we must surely date the possession of ideas from the earliest period of the existence of an animal ; and it seems absurd to deny to the embryo, before birth, a consciousness of the voluntary power it exerts in mus cular motion, or a power of feeling, and perhaps of being affected by sounds :— but, without indulging any wildness of conjecture, are we not compelled,—when we see an animal, in the first hour after its birth, seek the breast by the act of smell ing,follow a visible object with its eyes,and alter the adjustment of their axis accord ing to the distance of that object ; when the same infant being set upon its feet, immediately and correctly makes the mo tion of jumping,—are we not compelled to admit, as incomparably the greater pro bability,thatthese powers have subsisted, though not exercised, in the fcctai state, rather than that they should have been created at the instant of its birth ? This then is our situation with regard to innate ideas, and it would be a contradiction in terms to speak of innate notions or prin.