Quotation
Last reviewed:
“Entities are not to be multiplied beyond necessity.”
William of Ockham · Nominalism · Medieval · slogan later than the 14th century
What does it mean?
Do not add kinds of thing to an explanation when fewer will do the work: on the usual textbook reading, that is the razor, a rule of theory-building rather than a claim that the world is simple. A rival reading treats the slogan as Ockham's own sentence and as a general ban on invisible entities, sharper than his practice in theology. He does insist, in several technical wordings, that plurality is not to be posited without necessity. The neat English, and the famous Latin tag, are later capsules rather than a line from his pen.
Did William of Ockham really say this?
The library’s label is Questionable. Ockham repeatedly insists that plurality is not to be posited without necessity, in several wordings. The neat English sentence, and the Latin tag that matches it, are later capsules, not a sentence he is known to have written. The badge stays Questionable.
Where it comes from
Later formulation of Ockham's principle of parsimony
Approximate date: slogan later than the 14th century.
How to use it
A product team in Reading explains a drop in sales by inventing a hidden change in the customer's character, when the price rose and the bus route to the shop was cut. Ask whether the facts already in hand can carry the conclusion before a new hidden factor is recruited. An extra entity should be doing a job the simpler story cannot do, and the razor does not say the simpler story is therefore true.
A mindset reading
Simplicity is a guide, not a proof, and the simplest story can still be false. Using the slogan to shut down a hypothesis that is doing real explanatory work is as much a misuse as multiplying entities for sport. The badge matters because the familiar wording is a later capsule of a habit that, in his logic, is real.
Understand the philosophy
Ockham's nominalism, a caution about treating universals as extra entities in the world, is the philosophical home of the razor. The key term is parsimony, the refusal to posit more than an explanation needs. The slogan is how textbooks remember that habit. The Latin tag about entities not being multiplied beyond necessity is not a sentence he is known to have written, which is why the badge stays Questionable.
- knowledge
- mind
FAQ
What does it mean?
Do not add kinds of thing to an explanation when fewer will do the work: on the usual textbook reading, that is the razor, a rule of theory-building rather than a claim that the world is simple. A rival reading treats the slogan as Ockham's own sentence and as a general ban on invisible entities, sharper than his practice in theology. He does insist, in several technical wordings, that plurality is not to be posited without necessity. The neat English, and the famous Latin tag, are later capsules rather than a line from his pen.
Did William of Ockham really say this?
Questionable. Ockham repeatedly insists that plurality is not to be posited without necessity, in several wordings. The neat English sentence, and the Latin tag that matches it, are later capsules, not a sentence he is known to have written. The badge stays Questionable.
Which work is it in?
Later formulation of Ockham's principle of parsimony Approximate date: slogan later than the 14th century.