Now we can see the strengths and weaknesses of every ethic of duty.
This ethical conception successfully refutes a certain form of evil, which attempts to justify every misdeed by affirming that it conforms to duty. However, it appears vulnerable to a second form of evil, that which maintains something completely different and recognises that every misdeed is opposed to duty while affirming that duty has no value at all and that value is only granted to the violation of one’s duty and to the pursuance of one’s own interest.

The ethics of duty have managed to establish that the concept of duty is a consistent concept, irreducible to that of happiness or pleasure, and to prevent anyone performing an evil action from claiming to have carried out his/her duty in doing so and thus trying to justify his/her behaviour in this manner. However, the ethics of duty cannot counter evil, if it uses another concept, that of value, by which the notion of duty is judged and dismissed.

This applies to every kind of ethics of duty, in other words, to the moral doctrines which maintain that to found morality amounts to proving that we have a certain amount of duties, or that we ought to act in such and such a way.

The failure of the ethics of duty does not necessarily involve the failure of moral theory in general. Maybe another type of ethics, based on a different approach, would provide a better understanding of the question about the foundation of morality. Does morality involve searching for what makes us happy rather than defining our list of duties?

2/ The aim is not to determine what makes us happy

The question about the foundation of ethics may have a very different meaning from the question that we have just considered (wondering whether there is any moral obligation). We can also consider that to found ethics is to prove that morality is what enables us to achieve happiness.

I have named this kind of doctrine the “ethics of happiness”, and here again, I will not try to determine if utilitarianism is part of these ethics. We should then study the objective pursued by utilitarianism from its origin up to its more recent developments.

The ethics of happiness probably succeed in proving that happiness is what man prefers, and perhaps even that the meaning of the concept of duty is, in reality, happiness or pleasure. Nevertheless, we can define evil as the axiological position that maintains that the supreme value is the disappearance of mankind, and with it, the disappearance of every human desire, including that fundamental desire for happiness. It is not because man’s ultimate aim is to achieve happiness that we can conclude that the existence of man has any value whatsoever.

The ethics of happiness suffer from the same defects as the ethics of duty: they can only refute a certain kind of evil. The ethics of happiness can overcome egoism and provide a brilliant demonstration for this purpose, thus showing that the greatest happiness of all is in my own interest, and so, if I want to be happy, I need to search for the general happiness of all mankind.

However, the ethics of happiness cannot refute another kind of evil, which admits that my own happiness depends on the well-being of others while maintaining that what has a value is the destruction of our happiness, and beyond this, of mankind in general.