What is Individualism?

Individualism is sometimes described as what separates Western Civilization from the rest of the world. But what is it?

Typical definition:

individualism, political and social philosophy that emphasizes the moral worth of the individual.

The Center for Individualism should know, and it defines:

Individualism is an idea of society that champions individual liberty, creativity, and self-reliance. A thriving society cannot be engineered by the collectivist designs of central planners, sociology professors, or government economists. Rather, it is is the combined effects of individual actions and the spontaneous collaborations of free people that produce economic growth, cultural vitality, and social wellbeing.

A philosophy site says:

Although individualism has cropped up here and there throughout history, it first became known as a philosophy in the early 19th century, following the American revolution and Declaration of Independence, a statement of extreme individualism:

“We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness. — That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed.”

This is liberalism, a political philosophy almost synonymous with individualism.

I thought that individualism meant Ayn Rand egoism, where every man is selfishly out for his own interests. Individualism also means that strangers cooperate for mutual benefit.

About a millennium ago, Western Europe diverged from the rest of the world by becoming individualistic. That meant that people looked out for their individual interests, and also strangers learned to cooperate to form business markets, guilds, and governments. I suspect that the stranger cooperation was the most important part of individualism.

There are theories that Europe succeeded because people evolved higher IQ. That may be true, but I suspect that the larger effect was that Europe developed a higher collective IQ, as a result of strangers learning to cooperate towards common goals.

The paradox here is that Europeans became more cooperative as they became more individualistic. In the rest of the world, people would only cooperate within their clans, and progress was more limited.

Maybe there should be a better word for the individualism that made Western Civilization. And there should be a better understanding of what made it possible. Was it genes? Christianity? Other aspects of European culture?