Locke and the metaphysics of “State of Sensibility”
John Locke operates within a roughly Cartesian metaphysical framework of substances and modes. But concerning thinking substances and their modes, Locke’s view presents a twist on Descartes’ model of individual thinking substance and the significance of experience of oneself as a continuously existing thing. Since an act of thinking is modification of a thinking substance, without a substance there could be no activity of thinking. But the relation between thinking and thinking substance is nevertheless weak: although thinking substance is necessary for thinking, actual thinking is not necessary for thinking substance. Locke places sensibility at the heart of selfhood and personal identity. The sensible self is dependent on thinking substance as a basis for its realization, but the temporal continuity that is the sensible self is neither afforded nor constrained by the thinking substances that realize it.