This is a quote from the book "The ​Virtue Of Selfishness" by Ayn Rand
...e gained from social existence are: knowledge and trade. Man is the only species that can transmit and expand his store of knowledge from generation to generation; the knowledge potentially avai lable to man is greater than any one man could begin to acquire in his own life-span; every man gains an incalculable benefit from the knowledge discovered by others. The second great benefit is the division of labor: it enables a man to devote his effort to a particular field of work and to trade with others who specialize in other fields. This form of cooperation allows all men who t...
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