I’m sure we are evolving. We evolve in response to our environment, whether we make that environment or not.
Genes provide us with a variety of options so that we can respond to the environment. For example, our arms have the capacity to have big, strong muscles. If we exercise a lot, the genes follow the programming that helps us build big muscles. If we don’t exercise, the genes follow another program.
If we don’t need muscles that much—and in Western societies, that is the case, we might see our genes gradually losing that programming. We wouldn’t notice because we don’t need muscles. We have machines to do all that. The only people who would exercise that genetic capability are those who exercise, for whatever reason.
On a side note—it is important for humans to retain all kinds of capabilities, even those that are rarely used. We never know when we might need those capabilities. Like in a disaster that destroyed a lot of infrastructure, and we couldn’t get machines there, a person with muscles would be very important.
Now apparently there is some interaction between mitochodrial DNA or RNA (don’t know which) and the kinds of genetic programming that are brought out by the environment. I believe this interaction can result in evolution on a much shorter time scale. Some geneticist here could set me straight. I hope I haven’t made a total hash of it.
So given a lack of need for muscles in our environment; or, to use your example regarding air conditioning, our ability to be strong or to tolerate heat or cold might rapidly dissipate, perhaps to the point where it would be difficult to get it back when needed,
It’s an interesting thing how we adapt to our environment. Every year when it starts to get cold, I shiver at the thought of going out in the winter. Then, a month in, it doesn’t bother me at all, and I’m riding my bike in temperatures below freezing without feeling cold at all.
We are, no doubt, evolving on the long term as well. The most likely evolution is to our brains. Our brains give us extraordinary ability to survive, so we, as a people, will continue to get smarter and smarter and smarter, on average. That’s a form of evolution you can’t see from the outside.
Or maybe you could. Our skulls might get bigger, but I think they are at their limit in terms of us being able to be born. Still, there are c-sections, so maybe in the future, no one will be “of woman born.” Or maybe the response will be for skulls to start growing more rapidly after birth. Perhaps evolution will just find a way to make our brains more efficient within the confines of our skulls. Who knows what solution evolution will find?
So we are evolving all the time, I believe. Mostly in ways that are difficult to detect because the changes happen on such a long time scale (hundreds of thousands of years, not thousands). I don’t know if we are getting “better.” That’s a human judgment, and nothing that can be determined in an objective way.
However, I’m pretty sure we are enhancing our survivability and adapting more and better tools to deal with the environment we find ourselves in. Increasingly, that environment is one that we have modified. So in a sense, indirectly, we are messing with our own evolution. Soon we will be messing with our own evolution on a genetic level. We do it for other plants and animals already.
The your question will become much more important and viable. Humans will have to come to some kind of consensus about what a “better” human is. Of course, such a consensus will be impossible, so people will just start making changes on their own. We’ll have thousands of different genetic experiments going on. But hey! That’s ok. That’s what evolution is: lots of different experiments, each trying to find a better way to enhance survivability. Some of the experiments won’t work, and those people will die quickly. Others will prove to be more robust, and will be sold to humans more widely.
I’m half a century old. A little more. I believe we will see a market in genetic enhancements before I die. I hope so. I hope they find one that deals with cholesterol and weight and hypertension. That would be a gold mine! At least, in the West.