The final authority is Nature. Philosophy itself fails to question its own anthropocentric bias. A species persists or goes extinct based on whether it contributes more usefulness to its environment than it consumes. Humanity isolates itself with city walls for philosophers and aristocrats (God is the ultimate aristo, but doesn't have Nature's sensibility or physical power to act) to sit on while filling cities with corn-fed cattle. Scientists may be failing to justify themselves, but philosophers have absolutely failed to justify or explain human intentionality in Nature's context. Civilization is a cheat code and an evolutionary trap. As we approach peak consumptionism, philosophers will be requoting the same fluffy bunnies telling us how great and intelligent they were. Meanwhile, the only philosophy in practical use is an Invisible Hand Job of the mean Mean that knows the price of everything but the natural value of nothing.