In the comments below there is a debate about the inevitability of progress, the possibility of reversion to past states, etc. I am not going to put a long comment here, but want to enter several points.
- At the end of the day the universe will suffer “heat death,” so eventually all anti-entropic dynamics and phenomena will be reversed
- So we need to constrain the time parameter to something reasonable. The parameter for biological evolution is probably on the order of a billions of years, while for human history we’re talking thousands of years
- For biological evolution I think there has been a general trend toward greater complexity. Some changes seem to be irreversible. Off the top of my head: the emergence of aerobic life and multicellularity. Multiple extifnction events have not been able able to “turn back the clock,” because there’s always a residue of species. The key is that instead of gradual accumulation of complexity, it seems that rather there are “bursts” which reach plateaus. I think it can be argued that we have been at a plateau since the rise of terrestrial tetrapods (the extinction of very large insects is probably a function of the rise of tetrapods, who are “better” at filling the macro-terrestrial niches because of their superior scalability)
- When it comes to history this is much more tendentious, but yes, I do think there has been an arrow of change which has not reversed, and is unlikely to be, excepting in a post-apocalyptic scenario. You can see this cross-culturally, human sacrifice was relatively common across the ecumene during the “Bronze Age,” but disappeared or diminished during the “Classical Age.” This shift has never been reversed, at least so long as institutional frameworks remain robust enough to reconstruct themselves after a collapse.
- The integrative power of polities has improved very definitely over the past 5,000 years. Innumerable punctuated events of “collapse,” political, cultural, and social, allow us to test the proposition that civilization is becoming more robust in maintaining its coherency across the ages. And I believe it has. This is clear in China, where dynastic interregnums progressively have become more attenuated, and also in the West, where national-cores tend to retain integrity once they crystallize (e.g., northern France, central Spain, southwest Iran, etc.).
- The key seems to be that civilizations do not seem to regress in a stepwise fashion, and reverse, but rather collapse and lose total coherency. Once that process happens, and societies revert to tribal scale entities, then slavery, human sacrifice, organized animism, etc., pop back to the foreground. In other words, a total reversion back to a state of extreme savagery is plausible contingent upon a nearly absolute destruction of the institutions of civilization in toto and universally. It’s the extremity of the collapse which I think we should be skeptical of, at least within reasonable time scales (e.g., a few thousand years in the future).