A known unknown is something we know we don’t understand, like dark matter, dark energy, consciousness, abiogenesis, or quantum gravity. An unknown unknown is stranger. It’s something that could be true without violating known science, but that we may not even have the right instruments, concepts, perceptual bandwidth, mathematics, or metaphysics to notice. The sheer volume of these unknown unknown should humble anyone. But perhaps, the more suprising result is the trajectory