Human nature

Human nature is neither universally "good" nor "bad". We are just as capable of selfishness, greed, cruelty, and violence as we are of selflessness, kindness, and compassion. That this is true has utterly no bearing on the validity of either socialism or capitalism, as neither economic system requires that those living within them behave universally selfishly or universally altruistically, respectively. However, it does refute any ideology or philosophy (i.e., Objectivism) based on the assumption that all people will behave a certain way, all of the time.

That said, conceptions of human nature as either plastic or fixed identify locations on the traditional Left-Right political ideological spectrum. The ideological Left is committed to the proposition that human nature is plastic, that nurture trumps nature and behavior is what social institutions produce. The ideological Right is committed to the proposition that human nature is fixed, that nature trumps nurture and even optimal social institutions still produce less than admirable individual human beings. Each is right some of the time and wrong some of the time; the deciding factor in where you fit on the political spectrum depends on which one you think is correct more often than the other.

There are many who believe that human nature does not exist at all. Existentialism, in particular, believes that humans choose all aspects of their own psychology. Others, like the philosophers John Locke and Thomas Hobbes, believed that man, in his state of nature, was a selfish and warlike creature who would do anything in order to get ahead of others. They believed that civil society was a state that men women people would move into in order to escape the conditions of human nature. Enlightenment thinkers such as David Hume and Jean-Jacques Rousseau reasoned the opposite in that, in nature, mankind was peaceful and benevolent, that human morals lay in the passions, not within human reasoning. It was only at the advent of society that greed and selfishness became apparent.