"the rate of progress is accelerating: the number of scientific publications has doubled every nine years since the second world war. [..] many natural systems, such as the weather, are “chaotic” or sensitive to small changes: a tiny nudge now can lead to vastly different behaviour later. Since people cannot measure with complete accuracy, they can’t forecast far into the future. [..] Lord Kelvin, a great physicist, confidently announced in 1900: “There is nothing new to be discovered in physics now.” Just a few years later, physics was upended by the new theories of relativity and quantum physics. [..] Quantum physics presents particular limits on human knowledge, as it suggests that there is a basic randomness or uncertainty in the universe. For example, electrons exist as a “wave function”, smeared out across space, and do not have a definite position until you observe them (which “collapses” the wave function). [..] there seems to be an absolute limit on how much people can know. This is quantified by Heisenberg’s Uncertainty Principle, which says that there is a trade-off between knowing the position and momentum of a particle. So the more you know about where an electron is, the less you know about which way it is going. Even scientists find this weird. As Niels Bohr, a Danish physicist, said: “If quantum physics hasn’t profoundly shocked you, you haven’t understood it yet.” [..] There may be things people will never know, but they don’t know what they are."