For I imagine anyone would easily grant, that it would be impertinent to suppose, the ideas of colors innate in a creature, to whom God had given sight, and a power to receive them by the eyes from external objects: and no less unreasonable would it be to attribute several truths, to the impressions of nature, and innate characters, when we may observe in ourselves faculties, fit to attain as easy and certain knowledge of them, as if they were originally imprinted on the mind.

This statement neatly sums up Locke's entire purpose in the lengthy Book 2, though it is made at the very start of Book 1. In Book 1, immediately following this quotation, he attempts to demolish the position of innate ideas and principles on their own terms. In Book 2 he turns to the more important task of demonstrating how our faculties are, in fact, able to cull from experience all the ideas that fill our head. If he can really account for all of our ideas by tracing them to experience, he will undermine the need for innate ideas and strengthen the empiricist position considerably.