presumed quotes

Entia non sunt multiplicanda praeter necessitatem. No more things should be presumed than is necessary.

-William of Occam
This principle of intellectualeconomy, known as Occam's Razor, is not found in this form in his writings. Similar expressions can be found, eg Pluralitas non est ponenda sine necessitate ('Plurality should not be posited unnecessarily'), in Scriptum in Librum Primum Sententiarum.