16
Introduction
distinction is the relation between the conjunction of the premises of an argument and its conclusion. In revelatory arguments, this is the relation between a sign and its signified, in merely progressive arguments it is not. But that means merely progressive arguments do not preserve katalêpsis even though they could fulfil the infallibility requirement from chapter 3. The phrase that is used to explain revelation is ‘establish the conclusion through the dunamis of the premises’. The dunamis of a proposition is associated with its truth condition. This notion is spelt out into an outline of an account of truthmaking. The key is the connection between the Stoic account of causation, which is a three-place relation between two bodies that interact and a predicate that obtains because of the interaction, and the theory of lekta. A connection between the theory of causation and reports on the truth conditions for a type of proposition suggests that a body in so far it is acted upon by other bodies to exhibit a certain predicate can be considered the truthmaker of a proposition. And this would be meant by the dunamis of the proposition in the case of true propositions. Next, I explain what it means to establish the conclusion through the dunamis of the premises. In general, the antecedent in a conditional is revelatory if (the antecedent being evident and the consequent non-evident) the justification for the conditional is specific to the relation between the relevant truthmakers. Sextus gives an example of a proof that consists of a conditional and its antecedent as premises and the consequent as the conclusion. That conditional premise is ‘If sweat flows through the skin, there are intelligible pores’. This is true because of the causal interaction of the types of truthmakers for the antecedent and consequent. And the justification of that conditional specifies that causal interaction, namely that the occurrence of pores is among the causes for the occurrence of sweat. In contrast, the major premise of Sextus’ example of a merely progressive argument is ‘If some god told you that this man will be rich, this man will be rich’. Even though this is also true because of a causal relation between the relevant truthmakers, this proposition is sufficiently justified with a principle that invokes the general reliability of the gods. That is, the relation between the truthmakers is not essential to the justification of this proposition. The explanation for the revelation requirement that Sextus gives seems to pose demands on the justification of the conditional premise. And that is sufficient in these examples to ensure that the relation between all the premises and the conclusion is revelatory. In a proof, the revelation requirement effectively demands that the justification for all the complex premises – they may be present in the argument or can be supplied if they are not present – must be specific to the relevant truthmakers because this will specify the relation between the truthmakers of the premises and the conclusion. The relation is causal. Merely progressive arguments do not preserve katalêpsis because they violate the underlying requirement that the means of justification for a proposition must be accessible
