Man is flawed (history has proven it). If man is flawed then common sense common logic and rational reasoning is as well. I am not trying to find fault but the second above sentence is important to me. Feedback please. pljames
People are perfect. Just as children don’t appreciate how amazing they are, people don’t realize they are perfect. Common logic and rational reasoning, as well as irrationality and stupidity, are all expressions of this perfection - just as children are good even when they’re being “bad”, intelligent even when they answer questions “wrong”.
Did I answer your question about premises? 
why? sounds like a nonsequitur to me.
The body has an extraordinary intelligent functioning of its own separate from the intellect. The intellect is flawed because of some arbitrary model of an ideal state in comparison to the present situation. But for the comparisons that thought makes there is no problem with our life as it is; and there is no other life.
Not if logic and reasoning are the tools by which we measure whether man is flawed or not. That a man can make mistakes does not entail that he always makes mistakes all the time. That he is imperfect does not entail he cannot be perfect in some ways at some times. This is a non-starter, I’m afraid.