Pyanopsia was a Greek festival held in commemoration of Apollo on the seventh day of the month of Pyanepsion. The festival was connected with the myth of Theseus, who—before his trial against the Minotaur—gave thanks to Apollo by offering a dish of stew of beans and grains from Athens and an olive branch brought from the Acropolis. Thus, the name of the festival it inspired literally means “bean-stewing” from the Greek words pyanos (“bean”) and hepsô (“to boil”). Part of the festival involved a public feast of bean stew shared among all the people of Athens along with a procession of children carrying decorated olive branches, singing and dancing through the streets.
Since Apollo was the god of—among other things—reason and truth, we think it would be fitting to commemorate Chrysippus on this date. He had an immense the great influence on the development of Stoic logic and the systematization of Stoic philosophy as a whole. Thus, it is said that “Had there been no Chrysippus, there would have been no Stoa” (DL 7.183). On the year of his death (207 BCE), the Pyanopsia would have fallen on the October 22nd.
Here’s a passage from Diogenes Laertius’ Lives of the Eminent Philosophers (trans. Mensch; henceforth “DL”) that emphasizes Chrysippus’ influence on the field of study called “dialectic,” which uses logic and language to determine what is true or false:
He became so renown among the dialecticians that most people thought that if the gods had a dialectic, it would be none other than that of Chrysippus. [. . .] His industry was unequaled, as is clear from his writings, which number more than 705. He increased their number by repeatedly treating the same doctrine, setting down everything that came to mind, making many corrections, and citing a great many authorities …]”DL 7.180
Yes, 705 writings attributed to Chrysippus and yet none has survived today except as echoes in the extant texts of Seneca, Epictetus, and Marcus Aurelius.
His influence is still felt, though, via a form of modern logic still studied today called propositional logic or sentential logic (many of you likely studied in high school or in your college’s ‘critical thinking’ course). Though the Megarians were the first to formalize the rules of logical thinking using propositions, Chrysippus perfected it. [Note: Aristotle and Theophrastus formalized logic using categories (what’s now known as ‘categorical logic’), not using propositions.]
When I start talking on and on about propositions and how important propositional logic is at least one person asks me “What do you mean by the term ‘proposition’?”… That’s actually a very important question that modern academic philosophers might debate about. So let’s try to establish the definition of a proposition that Chrysippus would agree on.
Chrysippus defines a proposition as “that which is true or false, or a complete thing that can be affirmed on its own” (DL. 7.65). That is pretty much how modern philosophers use the term; a proposition is any complete statement that makes a claim that is either true or false. The examples that Chrysippus might have used are “It is day” and “Dion is walking.” Someone who says “It is day” claims that it is day. “And if it is day, the proposition being advanced is true; if not, it is false” (ibid.). Alternatively, “questions, inquiries, and the like are neither true nor false, whereas propositions are always true or false” (7.68). A very useful proposition to practical reasoning is called a “conditional proposition.” It is constructed using the conditional conjunction “if” and an example of a conditional proposition is “If it is day, it is light.” (Cf. DL. 7.71)
The importance of propositions becomes relevant when you start forming arguments with them. Here’s an explanation of “argument” that Chrysippus might have used:
An argument [. . .] consists of a major premise, a minor premise, and a conclusion, for example, “If it is day, it is light. But it is day. Therefore it is light.” The major premise is “If is is day, it is light.” The minor premise is “But it is day.” The conclusion is “Therefore it is light.”DL 7.76
Lastly, a valid argument is one whose conclusion you must accept if you assent to the premises. That is, the contradiction of the conclusion is impossible if the premises are deemed true.
Putting all these ideas together, you can adequately appreciate what Margaret Graver calls the Pathetic Syllogism (Cf. Ch. 2 of her Stoicism and Emotion). There are at least four versions of this syllogism (called “pathetic” because each version centers around a particular pathos) and they are all valid:
- “If a good is present, it is appropriate for me to elevate my psyche. A good is now present. It is now appropriate for me to elevate my psyche (this is experienced as delight or joy)”
- “If an evil is present, it is appropriate for me to contract my psyche. An evil is now present. It is now appropriate for me to contract my psyche (this is experienced as distress)”
- “If a good is in prospect, it is appropriate for my psyche to reach for it. A good is now in prospect. It is now appropriate for my psyche to reach for it (this is experienced as desire or wish)”
- “If an evil is in prospect, it is appropriate for my psyche to withdraw from it. An evil is now in prospect. It is now appropriate for my psyche to withdraw from it (this is experienced as fear or caution)”
Again, a valid argument is one whose conclusion you must accept if you assent to the premises. The task of a Stoic practitioner then is deciding whether or not the second premise is actually true: Is a good actually present or in prospect? Is an evil actually present or in prospect? If not, then the inference will not go through and you will not accept the conclusion. This task has come to be known as the Discipline of Assent.
Though you may not know what a “proposition” was, Chrysippus and the Stoics seem to think that we automatically interpret the world propositionally. In fact, the types of arguments above and the propositions they contain are the source of our emotional and moral lives. Thus, getting a handle on propositional logic will likely help us identify errors in our thinking and help us on our journey towards virtue and happiness.
So I express gratitude today to Chrysippus and to his Apollonian spirit. I’ll enjoy some beans in honor of him.