Plurality should not be assumed without necessity.

Whenever two hypotheses cover the facts, use the simpler of the two.

Entities should not be posited unnecessarily.

Entia non sunt multiplicanda praeter necessitatem

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

Plurality should not be assumed without necessity.

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