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

Entia non sunt multiplicanda praeter necessitatem

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

God's existence cannot be deduced by reason alone.

Entities must not be multiplied beyond necessity.

Never increase, beyond what is necessary, the number of entities required to explain anything.

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