The most profound reason... why the metropolis conduces to the urge for the most individual personal existence... appears to me to be the following: … - Georg Simmel

Man is something that is to be overcome.
Logically considered, this, too, presents a contradiction: he who overcomes himself is admittedly the victor, but he is also the defeated. The ego succumbs to itself, when it wins; it achieves victory, when it suffers defeat. Yet the contradiction only arises when the two aspects of this unity are hardened into opposed, mutually exclusive conceptions. It is precisely the fully unified process of the moral life which overcomes and surpasses every lower state by achieving a higher one, and again transcends this latter state through one still higher. That man overcomes himself means that he reaches out beyond the bounds that the moment sets for him. There must be something at hand to be overcome, but it is only there in order to be overcome. Thus even as an ethical agent, man is the limited being that has no limit.

All relationships of people to each other rest, as a matter of course, upon the precondition that they know something about each other. The merchant knows that his correspondent wants to buy at the lowest price and to sell at the highest price. The teacher knows that he may credit to the pupil a certain quality and quantity of information. Within each social stratum the individual knows approximately what measure of culture he has to presuppose in each other individual.

The brutality of a man purely motivated by monetary considerations … often does not appear to him at all as a moral delinquency, since he is aware only of a rigorously logical behavior, which draws the objective consequences of the situation.