According to Locke there are interesting analogies between deductive inferences and inferences concerning seventeenth-century machines. Where he believes that phenomena can’t be explained mechanically, as with gravity, he attributes the phenomena to the arbitrary activity of God. Locke emphasizes difficulties at the foundations of corpuscularianism, concluding that our idea of corporeal substance is obscure because we can’t use it to explain cohesion or impulse. On these foundations, he offers us an explanatory account of inherence, an account which would be completely attractive if not for th ... More

According to Locke there are interesting analogies between deductive inferences and inferences concerning seventeenth-century machines. Where he believes that phenomena can’t be explained mechanically, as with gravity, he attributes the phenomena to the arbitrary activity of God. Locke emphasizes difficulties at the foundations of corpuscularianism, concluding that our idea of corporeal substance is obscure because we can’t use it to explain cohesion or impulse. On these foundations, he offers us an explanatory account of inherence, an account which would be completely attractive if not for the false physics at its foundations. Given his austere theory of inherence, Locke believes that matter can’t naturally think. Explaining how God could make matter embody rational thought entails complications that Locke believes makes the hypothesis of thinking matter less likely than the hypothesis of Cartesian dualism. The discovery of the retinal image and improvements in the theory of perspective incline Locke to perceive a two-dimensional array. Since it’s possible to perceive things that way, he does. Because of the explanatory power of our ideas of primary qualities, he concludes that they resemble something in bodies, but no similar considerations apply to ideas of secondary qualities. On the traditional account, ideas represent their objects through resemblance, so the downfall of the scholastic theory of perception makes such judgments problematic. Locke offers an analysis of secondary qualities as powers to produce ideas in us as a way to save the truth and utility of secondary quality judgments.