Definition:Truth Value

In Aristotelian logic, a statement can be either true or false, and there is no undefined, in-between value.

Whether it is true or false is called its truth value.

Note that a statement's truth value may change depending on circumstances.

Thus, the statement "It is currently raining on the grass outside my window" has the truth value "false", whereas it had the truth value "true" last week.

The statement "I am listening to Shostakovich's 4th symphony" is currently "true", but that will last only for the next twenty minutes or so as I type.

The truth values "true" and "false" are usually defined in one of two ways:

$$\mathrm{T}$$ for "true" and $$\mathrm{F}$$ for "false";

$$1$$ for "true" and $$0$$ for "false".

There are advantages for both notations. In particular, the second lends itself to extending the discipline of logic into that of probability.