‘1. Combining several simple ideas into one compound one, and thus all complex ideas are made. 2. The second is bringing two ideas, whether simple or complex, together, and setting them by one another, so as to take a view of them at once, without uniting them into one; in which way it gets all its ideas of _relations_. 3. The third is separating them from all other ideas that accompany them in their real existence; this is called _abstraction_: and thus all its general ideas are made. This shows man’s power to be much about the same in the material and intellectual world: for the materials in both being such as he has no power over, either to make or destroy, all that man can do is either to unite them together, or to set them by one another, or wholly to separate them.’—Vol. i. p. 151. The first great point which Mr. Locke labours to prove in his Essay, is that there are no innate ideas, which he seems to have established very fully and clearly, if indeed so obvious a truth required any formal demonstration. His chief proofs are from the case of a man born blind, who has no idea of colours, and from the ignorance which children and idiots have of those first principles and universal maxims, which some philosophers and theologians, confounding the faculties of the mind with actual impressions, had supposed to be legibly engraven on the mind by the hand of its author. For the supposing the understanding to be a distinct faculty of the mind no more proves our ideas to be innate, than the allowing perception to be a distinct original faculty of the mind, which everybody does, proves that there must be innate sensations. These two positions have, however, been sometimes considered as convertible by the partisans on both sides of the question; the one arguing from the existence of the soul and the power of thought to the positive perception of certain truths, and the others concluding that by denying any original inherent impressions, they had overturned the supposition of the different faculties and powers which must be in the mind, to account for the first production or subsequent modification of sensation or of thought. For instance, it has been made a consequence of the doctrine that there were no innate ideas, that there could be no such thing as genius, or an original difference of capacity; as if the capacity were not perfectly distinct from the actual impressions by the very theory itself, and as if there might not be a difference in the capacity of acquiring ideas as all experience shows, though none in the knowledge acquired, because this capacity had never yet been exerted. As well might we argue that of two houses that are just built one is as commodious and capacious as the other, as well fitted for the reception of guests and the disposal of furniture, because at present neither of them is furnished or inhabited. The following passages will show the manner in which our author treats this part of his subject: