Once, however, mankind learned to create his own environment, he created a pleasant and stable one, so he just naturally stopped evolving. - Isaac Asimov

What a brain is made of isn't the essential thing: it's how the brain functions. Its thought patterns, its reaction time, its ability to reason and generalise from experience. Why does the whole issue have to be drown down to the level of organic cells versus positrons?

I stand four-square for reason, and object to what seems to me to be irrationality, whatever the source.
If you are on my side in this, I must warn you that the army of the night has the advantage of overwhelming numbers, and, by its very nature, is immune to reason, so that it is entirely unlikely that you and I can win out.
We will always remain a tiny and probably hopeless minority, but let us never tire of presenting our view, and of fighting the good fight for the right.

You don't ask a computer if it is sure of the answer it disgorges;