Darwinism

I'm a believer in Darwin's theory of evolution. As best as I can tell it's a tautology that has almost no rebuttal. This belief however has conflicted with my ideas of the benefits of a social society. From a Darwinistic stand point the argument might be said to favor the Libertarian view of society. It's an ideology that's all about individualism and the supposedly best rising to the top. So how could its counter, the ideal of a social pluralistic society that looks after the poor and the week compete with the ideas of Darwin. Tonight it occurred to me that indeed maybe evolution could act more on society as a whole rather then just on the individual. After all hasn't the rapid advancement of society been more about societal and social evolution.