Hume on Simple and Complex Ideas: A Wittgensteinian Reappraisal

Forthcoming in Systematic Thinkers in Early Modern Philosophy: Essays in Honor of Alan Nelson. Abstract: David Hume's science of human nature hinges on a strict separation between simple and complex ideas—a distinction likewise foundational to the empiricism of Locke and Berkeley. This paper examines how Wittgenstein's critique of absolute simples in Philosophical Investigations bears on this distinction. Wittgenstein argues that any distinction between 'simple' and 'composite' is relative to how we (inter-)define these terms, with multiple definitions possible in any context; hence, there is no absolute distinction between simple and complex elements of experience. Does this critique destabilize Hume's project? I argue that the answer depends on whether Hume's distinction between 'simple' and 'complex' ideas is intended to follow from the phenomenology of experience or to serve as a theoretical stipulation with specific explanatory or pragmatic aims. If the former, Wittgenstein's argument is devastating: 'experience itself' is compatible with various ways of drawing such distinctions, not all of which would support Hume's critical arguments. If the latter, however, Hume might have preempted this issue by justifying his theoretical stipulations on pragmatic grounds.