The advent of language as Ryan also pointed out is the real key. The group(s) that first deveolped it likely enjoyed a great evolutionary advantage as information could be relayed at vastly greater rates than the methods before it. It is also the case that the question one of both evolutionary advance (the steady increase in the cranium and brain volume) and cultural advance. At a point though (you might call this the tipping point, the industrial revolution, ect.) as in all logarithmic systems the total volume of information rocketed up.

I found the Wikipedia article on ‘Emergence’ fascinating (http://en.wikipedia.org/wiki/Emergence) and I think you will too. It’s believed that the same principal is responsible for the unique characteristics of the human brain compared to our close cousins. That may address you symphony question.

s for the cotton gin, there doesn’t seem to be anything specifically that kept it from being invented earlier. Perhaps mass production of cotton reached a point where previous technology couldn’t keep up. That is the nature of invention I guess. The Chinese had factories working 24 hours a day in 3 shifts over 1,000 years before the wests’ industrial revolution. Sometimes things don’t catch on.

You last point is very possible. There has been an almost total removal of selection pressure on humans from nature (read: no tigers chasing us, no freezing to death in winter, periodic starvation) to remove genes from the gene pool that previously would have left a human vulnerable. Genetic screening, targeted surgery and advanced pharmacology will likely undo most severely harmful traits in the years to come resulting in far longer life spans than previous generations.

Please feel free to reply if I have left something out (and sorry for all the parenthetical information, I am bad about that).

Of course as a Mormon I have my own ideas about who was behind the founding of the United States, as well as who was behind many of the inventions we enjoy, but nonetheless I’m trying to understand where atheists are coming from and how they explain things such as what I posted above.

Our cultural evolution is not gradual but spurred on by key discoveries. Controlling fire, the domestication of the dog, the beginnings of spoken language, the invention of the wheel, tribal government systems. All of these would have grown our cultural capabilities in jumps and leaps. Written language probably provided the first impetus for massive cultural growth, because it allowed knowledge to be transfered through time and across geographical space. The harnessing of electricity provided another in the 1800s. The invention of the car was yet another, and the invention of the internet was another. But you can see how the invention of written language made further innovation more likely. Likewise harnessing electricity made all kinds of inventions possible that weren’t before. And so on and so forth. So as we accumulate greater technology and a more sophisticated society, we become more likely to innovate further, thus the exponential cultural growth rate.

And to answer your other question, the simple answer is that musical abilities are likely tied to math and language skills. Having studied music theory for a good 10 years, I can tell you the skills are the same.

I’m also LDS by the way. I went to BYU and now I’m in med school in California. Just a little background information.