The sceptic will say, 'It may well be true that this system of equations is reasonable from a logical standpoint, but this does not prove that it corresponds to nature.' You are right, dear sceptic. Experience alone can decide on truth.
Either criticism is no good at all (a very defensible position) or else criticism means saying about an author the very things that would have made him jump out of his boots.
I wouldn't be worth my salt if I weren't attracting some controversy and criticism. Everyone in the world who has done something in life has attracted criticism.
An artist must only judge of what he understands, his field is just as limited as that of any other specialist... That in his sphere there are no questions, but only answers, can only be maintained by those who have never written and have had no experience of thinking in images.
It's useful for activists just to be out there to keep you mindful and not get complacent, even if ultimately you think some of their criticism is misguided.
There is a difference between responsible criticism that aims for success and defeatism that refuses to acknowledge anything but failure. Hindsight alone is not wisdom, and second-guessing is not a strategy.