Look around at what man's "reason" has gotten us. We sometimes knowingly make decisions that hurt ourselves and others. We often ignorantly make decisions that hurt ourselves and others. And that's aside from the fact that man is incapable of knowing and doing what's right without God's help. There is a way that seems right to man, but the end of that way is death and destruction.
"God's will is exactly what a good person would do if that person had all the facts, knew all the choices, and could predict all of the subsequent consequences."
Hmmm... Let's see...
Modern medicine.
The automobile.
Space travel.
Air travel.
The computer.
Yeah... let's face it... reason is worthless.