The great defect with which the ‘Essay on the Human Understanding’ is chargeable is, that there is not really a word about the nature of the understanding in it, nor any attempt to show what it is or whether it is or is not any thing, distinct from the faculty of simple perception. The operations of thinking, comparing, discerning, reasoning, willing, and the like, which Mr. Locke ascribes to it, are the operations of nothing, or of I know not what. All the force of his mind seems to have been so bent on exploding innate ideas, and tracing our thoughts to their external source, that he either forgot or had not leisure to examine what the internal principle of all thought is. He took for his basis a bad simile—that the mind is like a blank sheet of paper, originally void of all characters whatever; for this, though true as far as relates to innate ideas, that is, to any impressions actually existing in it, is not true of the mind itself, which is not like a sheet of paper, the passive receiver and retainer of the impressions made upon it. The inference from this simile has however been that the understanding is nothing in itself, nor the cause of any thing; never acting, but always acted upon; that it is but a convenient repository for the straggling images of things, a sort of empty room into which ideas are conveyed from without through the doors of the senses, as you would carry goods into an unfurnished lodging; and hence it has been found necessary by succeeding writers to get rid of those different faculties and operations which Mr. Locke elsewhere allows to belong to the mind, but which are in truth only compatible with the active powers and independent nature of the understanding. I will first state Mr. Locke’s account of the origin of our ideas in his own words, and will then endeavour to show in what that account is defective; that is, what other act or faculty of the mind I conceive to be necessary to the formation of our ideas, besides sensation or simple perception. After employing eighty pages in a very laborious, and for the most part sensible refutation of the doctrine of innate ideas, which was popular at the time, but which Hobbes has not deigned to notice, their impossibility being implied in the general principle that all our ideas are derived from the senses, Mr. Locke proceeds in the second book to treat of Ideas, and their origin. He then says: