Stoic Logic
Here are some links about Stoic Logic.
Is Stoic logic similar to other common logic systems? What's so special about Stoic logic? Are these links showing/explaining the original form/structure of Stoic logic?
https://www.historyoflogic.com/logic-stoics.htm
https://plato.stanford.edu/entries/logic-ancient/
Q
https://en.wikipedia.org/wiki/Stoicism
Logic
Propositional logic
Diodorus Cronus, who was one of Zeno's teachers, is considered the philosopher who first introduced and developed an approach to logic now known as propositional logic. This is an approach to logic based on statements or propositions, rather than terms, making it very different from Aristotle's term logic. Later, Chrysippus developed a system that became known as Stoic logic and included a deductive system, Stoic Syllogistic, which was considered a rival to Aristotle's Syllogistic (see Syllogism). New interest in Stoic logic came in the 20th century, when important developments in logic were based on propositional logic. Susanne Bobzien wrote, "The many close similarities between Chrysippus' philosophical logic and that of Gottlob Frege are especially striking."[14]
Bobzien also notes that "Chrysippus wrote over 300 books on logic, on virtually any topic logic today concerns itself with, including speech act theory, sentence analysis, singular and plural expressions, types of predicates, indexicals, existential propositions, sentential connectives, negations, disjunctions, conditionals, logical consequence, valid argument forms, theory of deduction, propositional logic, modal logic, tense logic, epistemic logic, logic of suppositions, logic of imperatives, ambiguity and logical paradoxes."[15]
Categories
Main article: Stoic categories
The Stoics held that all being (ὄντα) – though not all things (τινά) – is material. They accepted the distinction between concrete bodies and abstract ones, but rejected Aristotle's belief that purely incorporeal being exists. Thus, they accepted Anaxagoras' idea (as did Aristotle) that if an object is hot, it is because some part of a universal heat body had entered the object. But, unlike Aristotle, they extended the idea to cover all accidents. Thus if an object is red, it would be because some part of a universal red body had entered the object.
They held that there were four categories.
substance (ὑποκείμενον)
The primary matter, formless substance, (ousia) that things are made of
quality (ποιόν)
The way matter is organized to form an individual object; in Stoic physics, a physical ingredient (pneuma: air or breath), which informs the matter
somehow disposed (πως ἔχον)
Particular characteristics, not present within the object, such as size, shape, action, and posture
Somehow disposed in relation to something (πρός τί πως ἔχον)
Characteristics related to other phenomena, such as the position of an object within time and space relative to other objects
Epistemology
The Stoics propounded that knowledge can be attained through the use of reason. Truth can be distinguished from fallacy—even if, in practice, only an approximation can be made. According to the Stoics, the senses constantly receive sensations: pulsations that pass from objects through the senses to the mind, where they leave an impression in the imagination (phantasia) (an impression arising from the mind was called a phantasma).[16]
The mind has the ability to judge (συγκατάθεσις, synkatathesis)—approve or reject—an impression, enabling it to distinguish a true representation of reality from one that is false. Some impressions can be assented to immediately, but others can only achieve varying degrees of hesitant approval, which can be labeled belief or opinion (doxa). It is only through reason that we achieve clear comprehension and conviction (katalepsis). Certain and true knowledge (episteme), achievable by the Stoic sage, can be attained only by verifying the conviction with the expertise of one's peers and the collective judgment of humankind.
UQ
2. According to Anthony Kenny
https://en.wikipedia.org/wiki/Anthony_Kenny , "Where Aristotle used letters as variables in his logical texts, the Stoics used numbers; this is a trivial difference, but more importantly, where Aristotle's variables stood in for terms, Stoic variables stood in for whole sentences, or rather for elements that are capable of being whole sentences." ... ... "In late antiquity Aristotelian logic and Stoic logic were regarded as rivals, and while the Stoics' own writings have not survived, we have much evidence of polemics between supporters of the two systems."
By today the original writings of Stoic logic literature after destroying can now never been found. The existing writings are supposed following the structure and spirit of the original system.
Can we say the original system had never existed?
