The system of Fa is built up through the interaction of 256 signs, each of which is an essential mode of reality. Each element is the sum of a series of binary oppositions (open or closed cowrie shells, whole or broken lines, odd or even numbers, plus or minus, "male" or "female"); together they generate the whole world, including the vodu themselves. Thus, he who understands and controls the signs controls the vodu. In Fon myths, even the vodu are repre-sented as coming to Fa to understand their own dilemmas and get out of scrapes. But though "Fa is the king of life here below" (the vice-regent and homologue of God the king above)," his force is used always for harmony and regeneration of life. The very word "Fa" signifies "freshness," "sweetness or pleasantness," "cool-ness," and is the opposite of the "heat" of anxiety, tumult, anger, danger, or death. The bokono is consecrated to this "coolness": he is not an ecstatic, but must be given over to tranquil, pleasant, and benevolent consciousness, ethical behavior, and restraint. If he becomes angry or does an evil deed, the forces that he engaged through his meditative serenity will turn on him. It is his vocation to restore equilibrium in personal lives and especially in the society in general. Every regular ceremony of Fon worship, and determine which of the hundreds of vodu shall be propitiated, and how. Despite all their power and willful personalities, their sustenance, recognition, and therefore even their existence are dependent on the cool and wise science of Fa.
A Fa priest must know more than anyone else about the entirety of Fon religion, as a consequence, and the training of a bokono takes many years, which also traditionally included study abroad at Ifa centers in Yorubaland and elsewhere. The proverbs, stories, and myths appended to each of the signs must be learned; they comprise in their totality the entire mythical corpus of the Fon. The signs deal with the Creation and embody various of its moments and powers. Many of the Fa myths deal with the triumph of the cleverness embodied by Fa over the raw power and arbitrariness of the vodu. Here, in fact, are the sources for the Br'er Fox and Br'er Rabbit stories, and others of their type, popularized in American folk literature in the Uncle Remus tales. The signs govern not only the vodu, but also all the arts. They are all wisdom. The bokono is an authority on history, medicine, technology, and psychology, and the greater of them used to have extensive "hospital" quarters for lodging the sick and disturbed who needed their care.