The customs are changeable, that is, what yesterday it was considered certain, today it can be made a mistake, and that in a place where she is accepted the death of people, in this exactly country can have contrary laws in other regions. Then, the laws would be called provisory social conventions. They are not only the customs that vary, but also the values follow that them, the proper concrete norms, the proper ideals, the proper wisdom, of a people to another one. It would not be nothing more than what an adequate behavior to the effective customs. The ethics have a descriptive function: studies of cultural anthropology and fellow creatures, the customs of the different times and the different places. The humanity alone held back in writing depositions on the norms of behaviors of the last millenia, even so the men already exists has much more time. Certainly she must have a supreme ethical principle, being able to be the principle that forbids the incest.
However, if almost the totality, in the antiquity, was illiterate, as to know the family tree well? Scrates, using method of maiutica (to interrogate the interlocutor until this arrives by itself at the truth), was condemned to drink poison. It obeyed the laws, he questioned but them. For the Greek conservadorismo the laws existed to be obeyed, and not justified. Scrates was called, ' ' the founder of moral' ' , because its ethics if based on the personal certainty, acquired through a process of consultation to its ' ' demon interior' ' in the attempt to understand the justice of the laws. It would be then, first the great thinker of the subjectivity. Kant found that the equality between the men was basic for the development of universal ethics. Legality and morality if become opposing extremities. Ahead of each law, of each order, each custom, the citizen is obliged, to be a free man, to ask which is its duty, and to act only its duty in accordance with.