The Idle Argument is the classical argument for fatalism and the futility of action: ‘If it is fated that you will recover, you will, regardless of whether you consult a doctor. If it is fated that you won’t recover, you won’t, regardless . . . Either it is fated that you will recover or that you won’t. Therefore it is pointless to consult a doctor.’ In the first part of this chapter, the sources that preserve this argument are analysed in detail, and the various ways of understanding the argument, and the ambiguities in its expressions, are exposed. The main distinction turns out to be that between a reading of the argument as manifesting logical determinism, and a reading of it as manifesting causal determinism. Depending on which version one considers, in which way one understands the ambiguous phrases, and whether one takes them throughout in the same way, the argument may turn out as valid or invalid, its premisses as true or false, and it may or may not justify idleness. The second part of the chapter is dedicated to Chrysippus’ reply: He takes the Idle Argument to concern causal determinism, and to be a fallacy, and his refutation of it is designed to make clear the difference between common and garden fatalism (which is inconsistent) and Stoic causal determinism, which is consistent and does not lead to idleness, since human action and inaction are just as fated as everything else. It is shown that Chrysippus’ refutation does not require the existence of an empirically accessible, universal relation of necessitation, nor a causal theory with universal laws of nature.
Keywords: action, causal determinism, fallacy, fatalism, fate, logical determinism