This article focuses on the answer of Musil to the question : can we really do without good and evil ? Even if Musil has been strongly influenced by his reading of Nietzsche, he developed his own point of view about the nature and the value of the distinction between good and evil. Good and evil are not "absolute constants" but "functionnal values", and this distinction must be valued by herself : there are a bad evil, a bad way to be good, a good way to be bad, and perhaps a good way to be good. As a result it seems that we can not do without good and evil, even if they can not be taken as ultimate moral concepts.