# Ockham's Razor in Symbols

8/22/16

William of Ockham was a 14th century monk whose name is attached to a principle that guides skeptical and scientific thinking: Ockham's Razor.

Ockham's Razor states: "Pluralitas non est ponenda sine necessitate". This might be translated as: "Entities should not be multiplied unnecessarily".

Put another way, the hypothesis, consistent with the evidence, that uses the smallest number of assumptions is generally preferred. Note that this doesn't mean the hypothesis is correct, however. For all we know, the more complicated hypothesis might be the correct one. However, if both hypotheses equally explain the event, why go with the more complicated one? Why cloud your thinking? Moreover, selecting one hypothesis as the working hypothesis doesn't mean you have to completely get rid of or forget all other hypotheses.

Let's put Ockham's Razor into symbols. If we let E stand for the event, and H1 for the one hypothesis, H2 for the other hypothesis, then Ockham's Razor is:

If hypotheses H1(m) and H2(n), with assumptions m and n respectively, explain event E equally well, choose H1 as the best working hypothesis if m < n

Some similar "putting general principles into symbols" I came up with, are:

Anecdote vs. evidence:

For a claim C, evidence(C) > anecdote(C)

Reliability (or lack of) of memory:

For an event E that occured at time t1, reliability(memory(E,t1)) > reliability(memory(E,t2)) if t2 > t1

Rule of opinion:

Ceteris paribus, opinion(expert) > opinion(amateur)