Occam's Razor

Occam's Razor is the philosophical principle that, all things being equal, the answer with the fewest assumptions is usually the right one (often refered to as the "simplest" solution). However many scholars have disputed over the definition of "simplest". Some suggest "simplest" means the shortest possible description (called Kolmogorov complexity); other suggest that it means the description with on average shortest word length.^{[Citation Needed]} Still others have argued that the simplest model is the one which makes the most precise predictions with the fewest assumptions.

Examples

If you are walking down a country lane in New England and hear the sound of hooves behind you, you should assume that there is a horse behind you. There are other possibilities, for example zebras and unicorns, but both require more assumptions than a horse.

In the former case, one must assume that a zebra has escaped from a zoo (a vanishingly rare occurence) or been imported from Southern Africa by a mad millionaire, or some other unlikely scenario.

In the case of the unicorn, one must assume that unicorns exist - since there are no confirmed sightings of unicorns in the whole of written history, this is a huge assumption. There are many further assumptions to be made concerning, for example, how unicorns managed to breed unnoticed in New England.

Therefore, since the conclusion that the sound of the hooves is made by a horse requires the fewest assumptions, it is the most reasonable to assume.