In chapter 6 of book I of the Posterior Analytics, Aristotle contrasts proper demonstrations, which proceed from the cause, with syllogisms through signs, which do not proceed from the cause (75a31–34). An analogous contrast is drawn in chapter 17 of book II (99a1–4). Considering that in the Prior Analytics, in the context of the ‘official’ exposition of his doctrine of sign-arguments in chapter 27 of the second book, Aristotle defines a sign as a ‘demonstrative premise’, the claim that a syllogism through signs is not a demonstration might appear somewhat surprising. Maybe this is the reason why it was targeted by ancient commentators. Aristotle’s scanty remarks at APo. I.6 and II.17 about sign-arguments form the backbone of a doctrine which, as we shall show, was first set forth by Alexander of Aphrodisias and then re-stated by Themistius and Philoponus—a doctrine according to which the ‘syllogism of the that’ discussed by Aristotle at APo. I.13 is in fact a syllogism from a sign, and consequently APo. I.6 and II.17 ought to be read as contrasting proper demonstration, or demonstration ‘of the why’, with a second standard of demonstration, associated with the syllogism of the that or ‘from a sign’. The identification was made both implicitly, through the employment of Aristotle’s examples of sign-syllogisms from the Prior Analytics and the Rhetoric as examples of syllogisms of the that, and explicitly, thus becoming fully integrated into the commentary tradition.
Sign and Demonstration in Late- Ancient Commentaries on the Posterior Analytics
BELLUCCI, FRANCESCO;Costantino Marmo
2018
Abstract
In chapter 6 of book I of the Posterior Analytics, Aristotle contrasts proper demonstrations, which proceed from the cause, with syllogisms through signs, which do not proceed from the cause (75a31–34). An analogous contrast is drawn in chapter 17 of book II (99a1–4). Considering that in the Prior Analytics, in the context of the ‘official’ exposition of his doctrine of sign-arguments in chapter 27 of the second book, Aristotle defines a sign as a ‘demonstrative premise’, the claim that a syllogism through signs is not a demonstration might appear somewhat surprising. Maybe this is the reason why it was targeted by ancient commentators. Aristotle’s scanty remarks at APo. I.6 and II.17 about sign-arguments form the backbone of a doctrine which, as we shall show, was first set forth by Alexander of Aphrodisias and then re-stated by Themistius and Philoponus—a doctrine according to which the ‘syllogism of the that’ discussed by Aristotle at APo. I.13 is in fact a syllogism from a sign, and consequently APo. I.6 and II.17 ought to be read as contrasting proper demonstration, or demonstration ‘of the why’, with a second standard of demonstration, associated with the syllogism of the that or ‘from a sign’. The identification was made both implicitly, through the employment of Aristotle’s examples of sign-syllogisms from the Prior Analytics and the Rhetoric as examples of syllogisms of the that, and explicitly, thus becoming fully integrated into the commentary tradition.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
