Entia non sunt multiplicanda praeter necessitatem
God's existence cannot be deduced by reason alone.
Plurality should not be assumed without necessity.
Entities are not to be multiplied beyond necessity.
3 is a prime, 5 is a prime, and 7 is a prime. Why bother with non-prime numbers when the primes can do everything?
Never increase, beyond what is necessary, the number of entities required to explain anything.