William of Occam

William of Ockham - Sketch labelled "frater Occham iste", from a manuscript of Ockham's Summa Logicae, 1341

William of Ockham (ca. 1285-1349) was an English theologian and Franciscan monk. Today known as the originator of Occam's razor.

Attributed

• Entia non sunt multiplicanda praeter necessitatem.
  • Entities should not be multiplied beyond necessity.
  • Though widely cited as Occam's razor, the popular wording is not found in his extant works. Some succinct expressions of the concept in his actual works include:
    • Numquam ponenda est pluralitas sine necessitate.
      • Plurality ought never be posited without necessity.
      • Quaestiones et decisiones in quattuor libros Sententiarum Petri Lombardi (ed. Lugd., 1495), i, dist. 27, qu. 2, K
    • Frustra fit per plura quod potest fieri per pauciora.
      • It is futile to do with more things that which can be done with fewer.
      • Summa Totius Logicae, i. 12