equipollence
equipollency

In geometry, equipollence is a certain relationship between ordered pairs of points.

The concept of equipollence of bipoints can be also defined axiomatically.

Ancient Greek skeptics argued for equipollence, the view that reasons for and against claims are equally balanced.

It involves setting things in opposition and owing to the equipollence of the objects and reasons, one suspends judgement.

The terms equipollence (equalness-of-strength) and equipotence (equalness-of-power) are sometimes used instead.

One could also define "finite" independently of the notion of "natural number", and then define natural numbers as equivalence classes of finite sets under the equivalence relation of equipollence.