We are hurtling towards seven existential crises, each of which could wipe out the human race. They can be averted, but only if we can regain previous levels of belief in reason, intellectual confidence, and rigour. During the last hundred years there has been a steady decline in each of these aspects of reason. Martin Heidegger announced the “End of the Enlightenment Project” in the 1920s. The first question we need to answer is: Why? Whatever went wrong with reason in the early 20th century?
It is easy to forget that there was a massive crisis in science and mathematics around 1900. Both subjects posed knotty, impossible problems. Michelson and Morley had discovered that there was a fundamental relativity in the behaviour of light. This was something in complete contradiction with Newtonian physics, and the scientists were at their wits’ end. The mathematicians had discovered an equally deep contradiction in set theory, the foundation (they believed) of mathematics. Here too the task of finding a solution—which really explained the contradiction—looked hopeless. The mathematicians finally gave up, when they endorsed Zermelo-Fraenkel set theory in the 1920s. It introduced a new definition of sets which did not allow the contradiction to happen. No attempt was made to explain the situation: it was simply defined out of existence. The physicists meanwhile had endorsed Einstein’s theory of relativity which treated time as a kind of space. This meant that the future was already “in existence”—simply waiting to be revealed. No attempt was made to explain how we can have the freedom to do, or think, anything fresh, if the future is already there. Much spin was used to try to make the conclusion palatable, but it was like trying to make water run uphill. Both the scientists and the mathematicians had given up. They had reneged on their previous commitment to throw light onto the most pressing problems of their subjects.
These capitulations were carefully downplayed, but the message they brought was bleak ---there is no light at the end of the tunnel. A century of increasing neglect of reason has followed. How can one expect reasoning to proceed with vigour and confidence when the ablest brains have given up? Today the IT revolution means that we need to apply reason on an unprecedented scale to economic, technical and social practices. Both the knotty problems of the 1900s have actually been solved, belatedly, since 1990: but the now thoroughly demoralised subject hierarchies don’t seem to want to know.