With all things being equal, the simplest explanation tends to be the right one.

Pluralitas non est ponenda sine necessitate. A plurality (of reasons) should not be posited without necessity.

Simpler explanations are, other things being equal, generally better than more complex ones.

What can be explained by the assumption of fewer things is vainly explained by the assumption of more things.

Plurality is not to be posited without necessity.

Plurality should not be assumed without necessity.

It is vain to do with more what can be done with less.