Modal Idealism

According to Idealism, every fundamental entity is conscious, and moreover every fundamental property is a phenomenal property. The goal of this chapter is to defend “Modal Idealism,” which is the thesis that Idealism is metaphysically necessary. In particular, I give four different arguments for Modal Idealism. First, I argue that, if at least some possible fundamental properties are phenomenal properties, then the denial of Modal Idealism leads to implausible brute necessities. Second, I argue that those who endorse the Eleatic Principle, according to which it is necessary that all concrete objects have causal powers, should endorse Modal Idealism. Third, I argue that Modal Idealism helps us secure our knowledge of our own conscious states in the face of influential “debunking” arguments. Fourth, I argue that Modal Idealism is theoretically fruitful: it allows us to make substantial progress on several perennial metaphysical debates beyond the philosophy of mind.