Ancient Formal Logic

Description

DjVu lacks the Table of Contents

pp. 22-4 (DjVu pp. 27-9, PDF pp. 38-40) treat Aristotle's development/evolution of logic; cf. History of Formal Logic pp. 41-44 (DjVu pp. 67-70), which lacks the addition of § "4 E. Survey of the evolution" (Ancient Formal Logic pp. 23-4, DjVu pp. 28-9, PDF pp. 39-40)

How did Aristotle discover his logic?
This question was prompted by the passage about Aristotle in Stephen Wolfram, What Is ChatGPT Doing … and Why Does It Work? , § "What Really Lets ChatGPT Work?"

Bocheński, O.P., History of Formal Logic pp. 41-44 notes that although "We have no extrinsic criteria to help us establish the chronological sequence of the different parts of the Organon ", there are intrinsic criteria (ibid. p. 42):

The presence or absence of:

1. the syllogism
2. variables
3. a "technical level of the thought"
4. modal vs. assertoric logic
   Modal logic is more consonant with his hylemorphism than the assertoric logic that appeared in Plato's dialogues; thus, assertoric logic in Aristotle is an indicator the Aristotelian work is youthful, while modal logic would indicate a more mature work.

Bocheński concludes (ibid. p. 44):

It is only certain that the Topics and Sophistic Refutations contain a different and earlier logic than the Analytics , and that the Hermeneia exhibits an intermediate stage. For the rest we have well-founded hypotheses which can lay claim at least to great probability.

Bocheński, O.P., Ancient Formal Logic pp. 23-24:

4 E. Survey of the evolution

In the fight of the above chronology the evolution of Aristotle’s formal logic may be stated in the following way:

He first elaborated the Platonic λόγους (Top. , Met. Γ , De Int.), considerably developing and explicitly stating the rules or laws on which they are based. By doing so he stated a wealth of interesting logical principles of which, however, none is an analytic syllogism. This period may coincide with that of travels (348/7—335/4).

Later on he made his two great discoveries: that of the analytical syllogism and that of the variable. He then declared that the other (non-analytic) laws and rules are of lesser importance and concentrated on syllogism, first assertoric, then modal.

By analyzing the axiomatic system of the former (he did not have time, as it seems, to do so with the latter) he discovered several metalogical rules and even some laws of the logic of propositions. These last discoveries were, however, not systematized by him.