I think you're both right. We live completely differently now, but it's not clear that our essence has greatly changed.

In particular, that our values have changed is wonderful. But that's a cultural development. I'm convinced most of the people I've known would have shrugged at slavery like most Romans did, had they grown up with it. (Maybe they would have questioned it as children, but by adulthood they would have choked those questions down.)

Undoubtedly Khufu's subjects would be aghast if you shrugged at damming the Nile; perhaps the Romans would be aghast if you shrugged at oral sex, conscientious objectors, and female bosses instructing male employees; Hindutva activists today are aghast if you shrug at eating hamburgers, to the point that they may lynch you if they catch you slaughtering a cow. Some of our moral values are of course the correct ones, slavery being actually objectively immoral unlike those other examples, but generally people only know their culture's value system, not the objectively correct one. And some of our moral values are definitely not the correct ones.

The modern, western world still had slavery as recently as 150 years ago, so that too is not really a marker to differentiate between our era and antiquity.

Not to mention all the wars and genocides of the last two centuries, unprecedented in scale and ferocity, which make it hard to pretend we are morally better than any previous generation.

As I mentioned, the Burj Khalifa was built to a significant extent with slave labor, being completed only ten years ago, while the Great Pyramid probably was not, despite what the Greeks thought two thousand years later. In the United States there are some two million prisoners, most of whom also perform slave labor, as did the victims of GULAG.

Perhaps the Khwarazmians would disagree that the genocides of the last two centuries were unprecedented in scale and ferocity.

"Antiquity" is conventionally considered to end about 1500 years ago, though this really only applies to Europe: https://en.wikipedia.org/wiki/Late_antiquity

The reason for this is the very sparse historical record from the European Dark Ages. Scholars in the High Middle Ages like Petrarch could look back on their own recent history, and then a vast gap of mostly unknown, and then the impressive cultures of Antiquity among whose ruins they lived. We know more about the Dark Ages now than we did then but still not that much.

Here you can see people flying like birds without being canned in metal tubes: https://youtu.be/rvQ9DjJNal0 https://youtu.be/-C_jPcUkVrM https://youtu.be/gtvCnZqZnxc https://youtu.be/UYi9r2eiUhU

It seems likely that we have changed. I suspect Merer's workers, even if they had grown up in modern civilization, would not tolerate being employees, being disarmed, and having their children taken away for education; and probably more of them were dyslexic than in modern populations. But I don't really know.

Generally the rule is that domestic animals are stupider, smaller-skulled, more submissive, weaker, more neotenous, less aggressive, fatter, lower in testosterone, less sexually dimorphic, and possessed of smaller teeth than the wild type (https://en.wikipedia.org/wiki/Domestication_syndrome#In_anim...). Modern humans have these traits to a very notable degree compared to, as you allude to, chimpanzees and even Neandertals or Denisovans; but perhaps we have also been substantially domesticated over the last 4500 years, maybe even over the last 2000. Not because of driving cars, but because of having kings. Are we the Eloi? I don't think Wells thought of the aristocracy as the Morlocks.

Even if your genes were the same, would you be the same person if you had grown up never seeing an alphabet, never driving a car, two of your siblings dying in childhood, and never hearing of a government (like most of the world in Merer's time) or at least of a democracy (like Merer's workers)?

This would be the case if I was born in the countryside around Paris in 1400 or almost anywhere in the world around the same time.

As recently as 1840 still, France had a king (as did much of Europe), there were of course no cars, phones, etc., and over 60% of the French population could not sign their name.

Again, everything you are talking about in your original response relates to the very recent past, and that wasn't my point. I would agree the world changed beyond recognition in the last 50 years (although I would disagree it had much effect on us as a species).

But my original point was that the separation of history in "antiquity" and "our era" is arbitrary, and that we can relate to people from 4,500 years ago as well as our great great grand parents -- and perhaps more.

I see! I think you're right that change has been very fast recently, very much faster than anything innate about us can change, and of course that post-Renaissance Europe was in many ways very similar to Classical Antiquity. That's why it was called the "Renaissance", after all.

But there was a fairly sharp break between Late Antiquity and the Dark Ages, which I don't think is really arbitrary, except in the sense that it was only a local phenomenon and so only appears if your focus was Europe. It wasn't as big a change as the last century or two has been, but it was a big change. The progression of the Middle Ages was much more gradual, but it too eventually produced enormous changes, and certainly the Reformation and the consequent introduction of the Westphalian form of state were enormously consquential.

My great-great-grandparents were probably born around 1860, mostly in the US. So not only had they heard of governments, they knew about democracy and literacy, though some of them probably weren't themselves literate. They traveled and shipped goods by railroad, which was of course made of metal smelted from stones. They bought and sold things with coins and even paper money (though not fiat money). Some of them probably drove cars, though I've only heard definite stories of their children, my great-grandparents, doing so. Some of them made phone calls. Glass was mass-produced in their lifetimes, though greenhouses were still only for the rich, and steel-framed skyscrapers were built. They knew many illnesses were caused by "germs". Hot-air balloons were a century before their births; some of them may have lived to see not only heavier-than-air flight but also the Great War. I don't know if any of them ever underwent anesthesia, but it became widespread for surgery in their lifetimes.

So, I don't know that it's true that I can relate to Merer as well as to my great-great-grandparents. Merer didn't have iron, coinage, flight, germ theory, anesthesia, mass production, and so on. He probably didn't know the Earth moved or that the stars were suns. He might not have known the Earth was round. Even the Polynesians hadn't yet learned to navigate over open ocean. He didn't have wheeled vehicles; chariots would be introduced centuries later by the Hyksos.

AFAICT, the cut-off for "ancient" is the fall of the Roman Empire. Basically ~395 CE. Likely due to European civilization needing to rebuild post dark ages.

This is certainly problematic for many reasons, the largest being that civilization went along uninterrupted outside of Europe.