Presumably Kant here has in mind Locke's claim that sensation and reflection are the two sources of all our ideas,〔Locke, John. ''Essay concerning Human Understanding'', bk. II, ch. i, §§ 3-4〕 and is understanding Locke's reflection to be reflection on sensation only. This would be a misunderstanding of Locke, since Locke says that we get simple ideas from reflection on the "operations of our own Mind," a doctrine which is actually a precursor to Kant's view that the laws of our own intuition and thinking furnish the forms of knowledge to be added to the empirical contents furnished by sensation, although of course Locke did not go very far in developing this doctrine; in particular, he did not see that mathematics and logic could be used as sources of information about the operations of the mind.