Rational belief

[gargantuan]

Evolutionary change in biology occurs at the genetic level. When you start talking about ideas "evolving" you have to make sure that you separate the idea from the scientific definition of "Evolution."

I don't think you can separate the two. Genetic mutation has one effect on the human race, ideas have another.

Humans, as far as we know, are unique in the sense that they can affect their genepool directly through medicine. As a species we're involved in an evolutionary arms race with bacteria and viruses. I suspect genetic evolution itself would be too slow to respond to a lethal, air born pathogen with an incubation period of say 10 years. Our genes would fail us as a species, but our learning, the ideas contained in the memetic makeup of medicine would be our best defence. How you can separate that from traditional evolution I've no idea. The name of the game remains the same: Survival.

That's an extreme hypothesis though. In reality, even with genes, evolutionary pressures tend to be subtle. Religion has been, for my money, a subtle pressure, but a pressure none the less.

I would say religion is a recessive meme since it's effect on the memes of medicine has been to hold them back.

Rather than separate the two, I would say that genes and memes go hand in hand. And the smarter we get, the more important memes will become.