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

Entities must not be multiplied beyond necessity.

The explanation requiring the fewest assumptions is most likely to be correct.

Entia non sunt multiplicanda praeter necessitatem

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

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.