The biological ground of ethics, according to Prodi, should not be sought in feelings of empathy or altruism. On the contrary, human ethics is profoundly "unnatural", precisely because it is unbound from any genetic principle. As a matter of fact, if there was such a "natural" morality, there would be no free choice, since human behaviour couldn't but conform to these "natural" norms. But with no freedom of choice, to speak of ethics becomes meaningless. According to Prodi, ethics can exist because language—that is, hypothesis and choice—exists. The natural ground of ethics is our faculty to use a language.