If you read something like the Old Testament, even though there are things that are, for many in modern society, utterly bizarre and difficult to understand, there is still an overlap between many of the values expressed in that book (well, books) and the values of modern, liberal, humanist society (indeed much of the latter is drawn directly from Christianity, Judaism etc). In fact, even if you read something like the Iliad, which is arguably even more alien to the values of modern society than parts of the Old Testament, you still find large areas of overlap. Human values in many ways haven't changed significantly, but of course society has changed significantly and thus the way in which those values are put into practice has changed significantly alongside it. This is why morality is in the eye of the beholder; all of us are prisoners of the circumstances into which we were born, the circumstances in which we grew up and the circumstances that we live now, which inevitably reorders our moral priorities. Suppose some great societal shock threw back material wealth and technological progress across the board. I suspect in that scenario many of the advances that Scott identifies above would be thrown back with them.
Well I certainly don't believe that a reversion in technological progress would lead to reinstatement of slavery or the ideology that inspired it. Unless you're going full materialist (or relativist) here, there is inherent meaning in the development of human thought. A moral thought or idea might be influenced by material conditions, but the extent to which material conditions are tied to the evolution of moral human thought is not a testable theory.
Ideas are intangible things. And I think the ever-changing norms on gender and sexuality (i.e. 18-year-olds with 12-year-olds no longer being okay, teachers not being acceptable sexual partners to their prepubescent students, sex not only being defined as an act that involves a penis, thereby disqualifying lesbians as, uh, lesbians, etc.) is proof that, at the very least, material wealth and technological progress are not the sole drivers of evolution in morality or cultural norms.
The World Wars marked a turning point in how geopolitics works. Europe is no longer an incomprehensible mess of tribes constantly at war with each other, or fighting strong men like Napoleon or Hitler. They are nation states, and a proper historical education is why there is no "Lost Cause theory for the Third Reich" the same way there is for another country that no longer exists (ingrained in Southern culture and printed in textbooks nationwide).
I may have been a little too dismissive of the idea of moral thought being independent from material conditions. Obviously, it can be; just look at those 18th/19th century slave traders/owners who became abolitionists, often under religious influence, despite it not, perhaps, being to their own material benefit, and of course there are plenty of other examples of people who have gone out on a limb for the sake of 'beliefs' even if it wasn't in their material interest. Nonetheless I stand by the idea that morality tends to be a product of material circumstance. Whilst the Bible has been used to justify abolitionism, there isn't much in it that's particularly condemnatory of slavery and Jesus certainly didn't demand that, for example, the Centurion whose slave he healed then free the slave, and this isn't surprising given that slavery was widespread in the ancient world. Why was that? Was it because the ancients were simply evil or moral idiots? No, it was because slavery made a degree of economic sense in the societies of the ancient world, to an extent that it doesn't today (and whilst slavery did, largely, disappear in Western Europe after the ancient period, the replacements for it often fell upon a spectrum of not-exactly-free-labour), and thus people found reasons to justify it. Now, to a certain degree we don't
need slavery and other forms of unfree labour in the Western world today as we have a large supply of, comparatively wage labour that has been deracinated from any particular connection to the land (why, if you've got the money, would you need a house slave that you have to keep and feed when you can just pay a cook or a cleaner), whilst we also have technology that helps make obsolete a lot of the muscle labour that would previously have been required (think of the harvesting that would once have been done by hand that can now be done using a combine harvester). If we were to lose either or both of those things, and I can only assume that it would have to be some catastrophe that would cause that to happen, then slavery would suddenly begin to look more attractive. Obviously, there would be a degree of moral overhang as we've had it hammered into our heads that slavery is an absolute evil, but I suspect that the changed circumstances would eventually result in a recrudescence of the institution or something akin to it (with very-clever-big-brain
TM people like Aristotle or Calhoun coming up with moral reasons to justify it).
As for the changing norms on gender and sexuality - the age difference thing becoming a big no-no can at least be partly explained by the fact that people live much longer than they once might be expected to (particularly if you're poor), and thus the upper boundary of childhood has moved up somewhat. There's also the emancipation of women (since relationships of the kind you describe tended to be between an older man and a younger woman), which has occurred at least in part because societal expectations of women have changed; they're no longer expected to have lots of children, because child mortality isn't what it was (which, incidentally, means you don't have to start as early, and has also gone hand in hand with a decline in deaths in childbirth) and because, thanks to the emergence of welfare states and other support mechanisms, having children to support you later in life isn't the be-all-and-end-all. I suspect that the latter is, to a degree, also part of the explanation for the big shift in attitudes towards male homosexuality that has occurred (in the west) over the last fifty years.
As for Europe, there were about twenty independent states in Europe in 1900; there are now about fifty (and there could be more soon, given the existence of places like Scotland and Catalonia). If anything it's even more of an incomprehensible mess than it was before the wars! Geopolitics certainly has changed, but there's no guarantee that it won't snap back into a more conflict-oriented mode given the right circumstances; after all, before 1914 there had been only a handful of, relatively limited, wars between the states of Europe in the preceding century, certainly nothing on a comparable scale to what happened from 1914-1945. And, of course, there
is a 'Lost Cause' type mythology that surrounds Nazi Germany, which isn't as prevalent as the Confederate one, but that's arguably because the Confederacy was considerably less destructive than Third Reich was (which is not an endorsement of the former).
