After describing the corpuscularian background of Berkeley's work (in, for example, the writing of Boyle, Newton, Locke, and Malebranche), I consider whether Berkeley can endorse the existence of immaterial atoms or corpuscles. I suggest that he hopes to avoid a definite commitment. He wants his position to ‘float’, its level to be determined by the kind of empirical evidence that would strike materialists and immaterialists with equal force. This chapter foregrounds the role played by the notion of intelligibility, both in the defence of modern corpuscularian science (including the distinction between primary and secondary qualities) and in Berkeley's critical response to it.
Keywords: atom, Boyle, corpuscle, corpuscularianism, immaterialism, intelligibility, Locke, Malebranche, materialism, Newton, primary qualities, secondary qualities