Full Idea
A unit is that according to which each existing thing is said to be one.
Gist of Idea
A unit is that according to which each existing thing is said to be one
Source
Euclid (Elements of Geometry [c.290 BCE], 7 Def 1)
Book Reference
Euclid: 'Euclid's Elements of Geometry (Gk/Eng)', ed/tr. Fitzpatrick,R [Lulu 2007], p.194
A Reaction
See Frege's 'Grundlagen' §29-44 for a sustained critique of this. Frege is good, but there must be something right about the Euclid idea. If I count stone, paper and scissors as three, each must first qualify to be counted as one. Psychology creeps in.