What Fukuyama really meant: History is the development of ever more rational forms of societal organization. Western liberal democracy is the best possible such organization, so we can never hope to progress past it. This is because humans suffer from megalothymia, the psychological need to be better than everyone else, on which liberal democracy can put a lid by making competition positive for society. Yet liberal democracy frustrates people because it doesn’t allow one to completely dominate others. Combined with a lack of deeper meaning to life since the death of God (Neitzche’s Last Man), people will start feeling discontented, leading to the rise of extremist (and likely far-right, since the left only goes further in curbing megalothymia) political outlets.
Science & philosophy of science
Why Botzmann Brains Are Bad, Sean M. Carroll
Boltzmann brains (BBs) are brains that appear out of random fluctuations in the vacuum. In an very-long-lived universe where random fluctuations exist, we should expect many BBs to form spontaneously; many more, in fact, than brains formed through thermodynamically consistent processes soon after the Big Bang. A very small portion of these BBs would randomly be created with memories consistent with being born in the thermodynamic decrease phase. What is more, the currently mainstream theory (ΛCDM) probably satisfies these conditions (although some scientists disagree). The key point of the article is to point out the intellectual incoherence of any theory that predicts BBs (and hence of ΛCDM). Indeed, in such a theory, we should expect to be BBs ourselves, since we can’t distinguish between being natural observers in the early universe or BBs with completely fake memories. But if our memories are fake, there is no reason to trust the theories we develop, hence no reason to believe in ΛCDM in the first place.
So a physical theory that predicts Boltzmann Brains will significantly outnumber natural observers could be right, but can never be cognitively stable, and must always be rejected.