ABSTRACT In this paper, I raise and analyze two rarely discussed stories about the development of idealism in early modernity. I seek to show that Arthur Collier reaches the conclusion that the mind-independent world is strictly impossible following through the implications of Malebranche’s intellectualist considerations. One important component of divine rationality accepted by both is that God has to act in the simplest way possible, which, for Collier, shows that the existence of an imperceptible matter is extrinsically or metaphysically impossible. (...) By contrast, I will argue, George Berkeley resisted the temptation to construe the simplicity principle in an intellectualistic manner, even though it would have offered him an easy route to prove the impossibility of matter. Rather, when he argues that it is indeed God who is creating our perceptions directly on the basis that any belief in mind-independent substances is totally unjustifiable and we cannot form a coherent notion of it, he can be seen as radicalizing Locke’s voluntarism, according to which we have to appeal to the omnipotent God's arbitrary decisions with regard to various difficulties in philosophy. My proposal can also be read as an alternative to the well-known epistemological narrative about the emergence of idealism in the early modern period. (shrink)