And if the act was a serious mistake.

That's fatal! I see now that failure to accomplish what one sets out to do, as for instance in the building of my canal, may not be ruinous to a man.

A man may fail and be quite as able a man as ever, as those who succeed; for human beings can do only so much and no more.

Nothing that he has done or not done would alter the result.

And he need not take the failure greatly to heart.