A comment is made in this article on a recent book by B. Montanari on catgorical imperative (Potevo far meglio? Saggio sull’imperativo categorico, 2002). We must keep away from the two equally harmful extremes of taking thoughtless action and taking refuge in that hesitant, uncertain reflection that condemns us to take no action whatsoever, or to take no action in good time. That is why it is not enough for us to ask ourselves Can I do better? : we must also ask ourselves Could I have done better?. Once an action has been taken, criticism can be exercised to the full without running the risk of paralysing the action. We must not shut ourselves away from the question, remaining prisoners of the idea that what is done is done. On the contrary, for the very reason that it is done, we have an opportunity to think it right through again from the beginning with a critical spirit, not the spirit of destructive criticism, but that of constructive criticism, of the kind that does not set hurdles in the way of the smooth flow of life, but improves life.