Full Idea
If one begins the proof cosmologically, by grounding it on the series of appearances and the regress in this series in accordance with empirical causal laws, one cannot later shift from this and go over to something which does not belong to the series
Gist of Idea
If you prove God cosmologically, by a regress in the sequences of causes, you can't abandon causes at the end
Source
Immanuel Kant (Critique of Pure Reason [1781], B484/A456)
Book Reference
Kant,Immanuel: 'Critique of Pure Reason', ed/tr. Guyer,P /Wood,A W [CUO 1998], p.492
A Reaction
Badly expressed, but it is the idea that if you start from 'everything has a cause', you can't use it to prove the existence of an uncaused entity. Better to say: an uncaused entity is the only explanation we can imagine for a causal sequence.