摘要: In Comte’s definition of altruism there are only two extreme positions: egoism or altruism. Plato’s is an immensespace. Most the activities through which each one develops himself they neither altruistic nor egoistic. The coincidences and differences between definitions had led to various interpretations. method applied study it has been compare with egoism. Plato bridge, reference point clarify ambiguous aspects definition. Altruism does not replace justice, but perfects it. Free society taken as best social model. For long freedom, will also be manifested in life. Justice sufficient neutralize unjustices provoked by Social prudence should promote order build a more society.