Diodorus Cronus facts for kids

Diodorus Cronus (died around 284 BC) was an ancient Greek philosopher. He was known for his clever thinking and his work on logic. He belonged to a group of thinkers called the Megarian school. Diodorus was especially famous for his "master argument," which was a big idea about how we understand the future.

Who Was Diodorus Cronus?

Diodorus was born in a place called Iasus in Caria. He lived in the city of Alexandria during the time of King Ptolemy I Soter. The king supposedly gave him the nickname "Cronus," which means "old fogey." This happened because Diodorus couldn't immediately solve a logic puzzle during a dinner with the king and another philosopher named Stilpo. Some stories say Diodorus was so upset by this that he wrote a paper on the problem and then died from sadness. However, other accounts say he got the nickname "Cronus" from his own teacher, Apollonius Cronus. Diodorus likely died around 284 BC. We don't know exactly when he was born.

Diodorus was very famous for his amazing skill in logic and debate. People even called him "The Dialectician." This nickname was so well-known that it was also used for his five daughters: Menexene, Argia, Theognis, Artemesia, and Pantaclea. They were also skilled in logic! Some of his most famous students included Philo the Dialectician and Zeno of Citium, who started the Stoic school of philosophy.

Diodorus's Big Ideas

Diodorus was best known for his new ideas in logic. This included his "master argument," which he created to respond to the philosopher Aristotle's ideas about future events.

Diodorus also used a famous puzzle called the Sorites paradox (or "heap paradox"). He is also said to have invented two similar puzzles: "The Masked Man" and "The Horns." He believed that words themselves are not confusing. Instead, any confusion comes from people not explaining themselves clearly. Diodorus also thought that space could not be divided into smaller parts. Because of this, he believed that true motion was impossible. He also argued that things don't truly "come into existence" and that there isn't a lot of variety in time or space. Instead, he saw everything that fills space as one big whole made of tiny, indivisible pieces.

What Was the Master Argument?

The "master argument" was one of Diodorus's most important ideas. It dealt with a problem that Aristotle had thought about: Can we say that something that might happen in the future is "true" or "false" right now, especially if the future isn't set in stone?

Diodorus believed that anything "possible" was actually "necessary." This meant that the future is just as certain and fixed as the past. He thought that something is only possible if it is happening right now or if it will definitely happen in the future. For example, when we talk about something that happened in the past but wasn't recorded, we know it either happened or it didn't. We just don't know which one. Diodorus said the future is similar. Either something will happen, or it won't. Our uncertainty about it only shows our lack of knowledge. If something will never happen, then it's impossible.

The master argument itself is a bit tricky to understand because we don't have Diodorus's exact words. But a philosopher named Epictetus described it using three main statements:

• (1) Everything that was true in the past must be true.
• (2) Something impossible cannot follow from something possible.
• (3) Something is possible even if it isn't true now and never will be true.

Diodorus believed these three statements couldn't all be true at the same time. He used the first two statements to show that the third one must be false.

How Did the Master Argument Work?

One way to understand Diodorus's argument is like this: If a future event is not going to happen, then it was true in the past that it would not happen. Since every past truth is necessary (statement 1), it was necessary that in the past it would not happen. And because something impossible cannot come from something possible (statement 2), it must have always been impossible for that event to happen. Therefore, if something will not be true, it can never be possible for it to be true. This means statement 3 is false.

Other philosophers had different ideas. Panthoides, Cleanthes, and Antipater of Tarsus used statements 2 and 3 to argue that statement 1 was false. Chrysippus, on the other hand, agreed with Diodorus that past events are necessary. But he disagreed with Diodorus's idea that something possible must either be true now or be true in the future. So, Chrysippus used statements 1 and 3 to show that statement 2 was false.

See also

In Spanish: Diodoro Cronos para niños