This idea has a lot of legs if you examine it. One of the more interesting points I've heard from Jordan Peterson in one of his criticisms of postmodernism is this: Postmodernism observes that after centuries of trying, we don't seem to have an objective standard for ethics or philosophy (or at least one that we can all agree on). Postmodernism, to the extent that one can refer to the whole movement in a short sentence, then tends to assume that therefore there are no distinctions between moral frames or perspectives, and from there proceeds to go in a different direction and analyzes everything simply in terms of power, because they decided that's the only thing that matters since moralities and philosophies otherwise have no meaning.

Don't get too tied up in the details of that summary; I'm well aware of just how brutal that summary is. But the details of the summary aren't what's important; what's important is the observation that there are absorbent barriers in philosophy and especially morality. You can't pursue a morality that results in your death, especially if it results in a quick death. There's some others too, but that's biggest and the most obvious. Civilizational death is another one; more abstract, but also a rich vein of observations.

For example, there's a lot more people living people advocating for humanity to be killed off for the planet than dead people advocating for humanity to be killed off for the planet's sake. It is impossible for the living to observe any other outcome.

This does not lead us via simple, universally-agreeable philosophical steps to a universally-agreed upon morality. But it does create distinctions between different moralities and philosophies, and once you admit that into the world, it once again becomes valid to study different philosophies and moralities again without having to accept the postmodernistic "throw your hands in the air and give up ever being able to determine anything, and then go study something else instead". It's still nowhere near a mathematically rigorous world by any means, but it's no longer hopeless.

(Bonus observation 1: No, this is not simply utilitarianism. Consider utilitarianism as a spectrum of "how concerned am I about 'utility'". Utilitarianism is the idea that we should be very far to the side of considering that, if not considering it solely; on a spectrum from 0 to 1, utilitarianism is that we should be close to or on 1. This observation is the complementary observation that we can not be close to or on 0. But we might still be on, say, 0.5, which is not "utilitarianism" but may be enough to create philosophies that still keep us alive. This observation also does not depend on "valuing" life over death, because it is on a far more primal and brutal level than that. It is the factual observation that if you hit one of these absorbing barriers you are no longer a participant in philosophy, not a normative statement about whether that is or is not a good thing.)

(Bonus observation 2: This is the beginning of the path, not the end.)