Aristotle's Two Modal Theses Again

TLDR: In this paper, an interpretation of the arguments Aristotle offers in Metaphysics 9.4.4, 1047b14-30, for the two modal theses [1] if A is the case then B was the case, then (if A is possible then B is possible) [2] if B was possible then A was possible, and [3] if C is possible, then C was possible.

Abstract: This paper offers an interpretation of the arguments Aristotle offers in Metaphysics 9.4, 1047b14-30, for the two modal theses [1] if (if A is the case then B is the case) then (if A is possible then B is possible) [2] if (if A is possible then B is possible) then (if A is the case then B is the case) Aristotle's arguments for these theses have not typically impressed commentators. I offer two arguments which are relatively faithful to Aristotle's text. The arguments rest on the following pair of claims concerning conditionals and possibility respectively [COND] 'if A then B' is true if and only if in any circumstances in which A obtains, B obtains also [TEST] 'possibly A' is true in a range of circumstances C 1 . . . C n if and only if assuming A true in any C i gives rise to no impossibilities, once any further required adjustments are taken into account The arguments and the premises on which they rest are stated without formalisation of the theses [1] and [2]. The argument for [1] is a defensible and persuasive argument. The argument for [2] is invalid, though plausible. That is consistent with our differential verdicts on [1] and [2]. [2] appears to be false: the argument provided for [2] explains why Aristotle might nevertheless have asserted it. The aim of the paper is to justify a more positive verdict on Aristotle's arguments than is usual among commentators.