Maarten Maartensz:    Philosophical Dictionary | Filosofisch Woordenboek                      

 O - One


One: Some single thing; what a single thing counts as.

The term "one" has mostly a counting sense, and the number 1 or numerical concept 'one' is one of the few numbers all men always and everywhere, in all languages so far as is known, have recognized. (Some human civilizations had not much use for more than "one", "two", "three". And indeed a few people can recognize precisely five things at a glance, but most can distinguish one, two or three things at a glance.)

It is somewhat interesting that the numerical concept one can be defined or closely approximated by a formula that only contains logical terms including identity: In case any predicate F satisfies this formula (Ex)(Fx & (y)(Fy --> x=y)) it is true of precisely one thing - for the formula says there is some thing that is F and every thing that is F is the same as that thing.

See also: Number


Hirsch Ed.

 Original: Aug 25, 2007                                                Last edited: 12 December 2011.   Top