Full Idea
If mind and brain exactly correspond we have as good ground for saying the brain depends on the mind as the other way round; if predominance is given to the brain, the reason is that it fits into a wider explanatory system.
Gist of Idea
Why shouldn't we say brain depends on mind? Better explanation!
Source
A.J. Ayer (The Central Questions of Philosophy [1973], §VI.D)
Book Reference
Ayer,A.J.: 'The Central Questions of Philosophy' [Penguin 1976], p.130
A Reaction
A small but significant point. If an 'identity' theory is to be developed, then this step in the argument has to be justified. It is tempting here to move to the eliminativist view, because we no longer have to worry about a 'direction of priority'.