“A consequence of this alienation of humans from their own nature is that they are also alienated from each other. Productive activity becomes ‘activity under the domination, coercion and yoke of another man’. This other man becomes an alien, hostile being. Instead of humans relating to each other co-operatively, they relate competitively. Love and trust are replaced by bargaining and exchange. Human beings cease to recognize in each other their common human nature; they see others as instruments for furthering their own egoistic interests.”
— From Peter Singer’s A Very Short Introduction on Karl Marx.