Full Idea
The Julius Caesar problem is the problem of supplying a criterion of application for 'number', and thereby setting it up as the concept of a genuine sort of object. (Why is Julius Caesar not a number?)
Clarification
This refers to Frege's Grundlagen §66
Gist of Idea
The Julius Caesar problem asks for a criterion for the concept of a 'number'
Source
B Hale / C Wright (Logicism in the 21st Century [2007], 3)
Book Reference
'Oxf Handbk of Philosophy of Maths and Logic', ed/tr. Shapiro,Stewart [OUP 2007], p.179
A Reaction
One response would be to deny that numbers are objects. Another would be to derive numbers from their application in counting objects, rather than the other way round. I suspect that the problem only real bothers platonists. Serves them right.