True, False, and I don't know

Any good scientist starts with "I don't know". That's the fundamental beginning.

You write down a premise, except some of the variables are Neither True nor False, and some of them are Both True and False.

The amazing thing is, you can still verify that your premise is Valid. Even though you don't know some of the things, you can still say something valid!

Using the same logic, you can also expose fallacies like "It's been true for 20 years, so it will be true tomorrow (and forever)" as formally-provably invalid statements

MySQL uses 3-valued logic too 🚥 🚦 because the real world has missing values (it's Graham Priest's LP system) #LP #contrapositive #GrahamPriest #MySQL