I take it that 'necessary' is a familiar term whose meaning we learned at our mother's knee.
So, I do not define the term further.
But others are welcome to define the term in a way that makes sense to them. I only require
that your definition allows the following
to come out true: if something is the case
no matter what possible situation is actual, then that something is necessarily the case.
For example, if it's the case that triangles have three
sides no matter what possible situation is actual, then it is necessary that triangles have three
sides.
Also, the notion of 'necessity' here is objective necessity: that is to say, if something is necessary,
then it must, by nature, be so -- no matter what anyone may or may not know. For example, it is necessary
that certain axioms entail the Pythagorean Theorem, whether or not I happen to know this.
|