What do we know in general about the law of karma? For the general public, it is nothing more than a blind destiny, pursuing the individual. The student of traditional doctrines sees in it an application of the law of cause and effect. It is no longer a question of fate, but a universal principle which man can use, of his own free will. Nevertheless, the secrets of its mechanics go much deeper and do not concern the consequences of acts as much as the act itself, in its multiple dimensions. How has this principle evolved over the course of history, and what are its different aspects? This two-part question represents the subject of this work which carries out a philosophical examination of the act. Far from naive explanations such as the miracle-solutions endlessly proposed here and there, the problem of karma ties into its diversity, but also its universality.