Man is a wolf to man, Erasmus included this phrase in his collection of adages, but its celebrity is due to the modern British philosopher Thomas Hobbes (1588-1679).
Thomas Hobbes maintained that the appetites and aversions of one individual collide with those of another and for Hobbes this collision and its consequences supply the fundamental reason for civil society. Though men are relatively equal in body and mind, this equality does not lead to harmonious relations but to warfare, because each man, entertaining an equality of hope in the attainment of his ends, becomes an enemy of every other man. The particular desires that cause the most trouble are those that relate to wealth: the desire to be secure in one’s person and property, and the desire to be deferred to and enjoy respect. Hobbes asserted that in the nature of man we find three principal causes of quarrel.
The first of these causes make men invade for gain; the second for safety and the third for reputation. Unless there is a common power to keep them all in awe they are in a condition which is called war. By war Hobbes meant not just the actual state of war but also the continued prospect of war.