In a well-known passage of the II book of Ethics to Nicomacus, Aristotle states that there are certain actions that cannot be considered in their fair half, but always constitute a disorder and are, thus, illicit under every circumstance. The idea of absolute morals, that has inspired an important part of the ethics in the Western Hemisphere has been strongly questioned by different authors, that maintain that it expresses only a tautology or that it is simply false, since it doesn't meet up to the complexity of human actions and its circumstances. This article intends to show that there are good reasons to sustain this old Aristotelian idea which explains much better than its detractors the scope of our responsibility.