After Julius Caesar was killed, Cicero retired to his estate in the country to write. There he wrote “On Divination”. It records a discussion he had at the time with his brother Quintus about whether divination is true: do the gods tell us about the future through oracles, visions, astrology, prophets, the flight of birds and so on?
Quintus argues the Stoic position: divination works.
Cicero argues the opposite: it does not work. Diviners are right only through mere chance, not through any true knowledge.
His arguments sound like what someone today would say, yet Cicero still believes in the old Roman gods. He makes that plain. He just does not think that the gods would tell us things in such a roundabout way. In art and science we already have all that we need to know to live in this world.
Quintus says that if the gods exist, then they would tell us about the future. As it happens, they do: through divination. Therefore the gods do exist.
Quintus points out that men in all times and countries have believed in divination. Not only that, but it somehow works, though Quintus himself has no idea how. He gives many striking examples from history and even quotes Cicero’s own words in support.
Quintus’s argument takes up the first half of the book. It all sounds good. But then in the second half Cicero shows all the holes in it:
- Just because most men believe something does not make it true. As philosophers we must argue from reason, not from the opinions of shopkeepers.
- You give examples of where divination works, but not where divination fails, as it does most of the time.
- All men believe in divination, but they do not at all
agree on what this or that sign means. There is no body of proven knowledge common to all nations.
- You say divination is built up by observations down through the ages. Is that so? Where is the proof of that? When observation leads to provable knowledge it becomes part of an art or science. It is no longer left to divination.
He uses the two twins argument against astrology. And on it goes.
Though most present-day readers will agree with him, Cicero’s own argument is also weak. Quintus gives in and never argues against it. I will have to fill in for him:
The holes in Cicero’s argument:
- Cicero doubts divination because Quintus does not know how it happens. Should I doubt Cicero can think because he does not know how the mind works?
- Cicero does a lot of supposing about how gods act and think and uses this to show that divination is unlikely. Yet he assumes that the gods think just like man. In fact, just like one man: Cicero!
This last argument, the-gods-agree-with-me argument, is still being used against religion 2000 years later.