Full Idea
The proposition that different times cannot be simultaneous is synthetic, and cannot arise from concepts alone. It is therefore immediately contained in the intuition and representation of time.
Gist of Idea
That times cannot be simultaneous is synthetic, so it is known by intuition, not analysis
Source
Immanuel Kant (Critique of Pure Reason [1781], B047/A32)
Book Reference
Kant,Immanuel: 'Critique of Pure Reason', ed/tr. Guyer,P /Wood,A W [CUO 1998], p.162
A Reaction
It seems possible that this proposition is in fact analytic. What would it be like for two times to be simultaneous? If it happened we would not accept it, because it would violate our very concept of an instant in time.