Stoicism

Stoicism was one of the great schools of Hellenistic Philosophy which appeared in opposition to Platonism.
Founded by Zeno of Citium (334-262 BCE), Stoicism became the greatest rival to Aristotelian Logic.

Zeno of Citium (335-264 BCE) was the Founder of the School of Stoicism in Athens, Greece.
Chrysippus (c.290-207 BCE) was the third Master of the Stoa after Zeno.

Zeno taught from the ‘Stoa Poikile’, meaning ‘Painted Porch’, on the north side of the Ancient Agora of Athens.
A Stoa was the Porch of a building, either a covered walkway or Portico. The Entrance to the Stoa was open with Doric Columns lining the sides creating covered walkways.
It was decorated by Paintings of the Fall of Troy and the Battle of Marathon with Statues of Heroic figures.
It was destroyed by the Heruls in 267 CE during the Sack of Athens.

In contrast to Aristotelian Deductive reasoning, the Stoic Syllogism, draws a conclusion by inference, stating an ‘Assertable’ or a ‘Sayable’.
This known as Propositional Logic.
‘If’ such and such, ‘Then’ so and so. There were five forms of argument or ‘Indemonstrables’:
1. If it is day, then it is light: It is day, therefore it is light.
2. If the first, then the second: Not the second, so not the first.
3. Not both the first and the second: The first, so not the second.
4. Either the first or the second: The first, so not the second.
5. Either the first or the second: Not the first, so the second.

The third Head of the Stoic School, Chrysippus of Soli (279-206 BCE), was known as the second Founder of Stoicism. Chrysippus developed the five ‘Indemonstrables’, meaning basic forms of argument.
None of his works have survived, of which two known Works were ‘Logical Questions’ and ‘On Providence’.
The Stoic school of philosophy fell into disfavour by the seventh century CE.
Our knowledge of this school comes from references made by authors such as Diogenes Laertius.