 I shall not at present meddle with the physical consideration of the mind; or trouble myself to examine, wherein its essence consists, or by what motions of our spirits, or alterations of our bodies, we come to have any sensation by our organs, or any ideas in our understandings; and whether those ideas do in their formation, any, or all of them, depend on matter or no [emphasis added]: These are speculations, which, however curious and entertaining, I shall decline. (Book I, chap. I, 2; see also II.XXI.73)