Occam's Razor
Occam's Razor (also spelled Ockham's Razor) is a principle attributed to the 14th-century English logician and Franciscan friar William of Ockham. It forms the basis of methodological reductionism, and is also called the principle of parsimony or law of economy.
In its simplest form, Occam's Razor states that one should make no more assumptions than needed. Put into everyday language, it says
Numquam ponenda est pluritas sine necessitate. [Latin]
which translates to:
Multiples should never be used if not necessary.
or
"Shave off" (omit) unnecessary entities in explanations.
But the more commonly used translations are:
Given two equally predictive theories, choose the simpler, and The simplest answer is usually the correct answer.
;-)
Of course, I spent the afternoon at the dentist's office and the cocktail hour has already begun here...