Reality Does Not Conform to the Idea, but Confirms It

In September 1846 the French mathematician Urbain Le Verrier, who had calculated from irregularities in the orbit of Uranus that an unseen planet must be pulling on it, sent his prediction to the Berlin Observatory. On the night he was received, the astronomer Johann Galle pointed his telescope at the position Le Verrier had given and found a new planet within one degree of it. It was Neptune. The planet had been there all along, and the idea had been conceived without a look through any telescope. The episode shows the sense of the topic's remark, attributed in spirit to Hegel, that reality does not conform to the idea but confirms it.

The remark reverses a common assumption. We usually think that ideas must conform to reality, that a good theory is one that matches the facts. The topic suggests that sometimes the relationship runs the other way, and that the idea is prior, with reality bearing witness to it. This is not magic. In the case of Neptune, the idea was a deduction from Newton's laws, and when reality showed the planet, it confirmed that the laws, and the reasoning, were right. The structure of the world matched the structure of thought.

Science has many such moments. In 1964 Peter Higgs and others proposed a field to explain why particles have mass, and said that it would imply a new particle. Nearly fifty years later, in 2012, the Large Hadron Collider at CERN found it. Einstein's general theory of relativity, completed in 1915, predicted that accelerating masses would send ripples through spacetime, and in 2015 the LIGO detectors recorded gravitational waves from two black holes that had merged more than a billion years earlier. Dirac's equation of 1928 predicted antimatter before any had been seen. Each time, the world was found to be as the mathematics said.

These cases led the physicist Eugene Wigner to speak of the unreasonable effectiveness of mathematics. If mathematical structures devised in the study often turn out to describe nature, then perhaps nature is in some sense rational, and the mind is attuned to it. Hegel held that the real is rational and the rational is real, and that the world is the unfolding of an Idea. For him, history and nature were the self expression of reason. The remark in the topic fits this view. The Idea is not a copy of reality but its inner truth.

The Idea is not a copy of reality but its inner truth.

The pattern appears in politics and society. The idea of a free and equal citizenship was proclaimed in the American and French declarations of the eighteenth century at a time when reality contradicted it. Over the next two centuries, reality was reshaped until it came closer. Slavery ended, the franchise widened, and colonies became nations. Some would say that reality was brought to conform to the idea, but the topic suggests something different, that the idea expressed what was latent in human beings, and that reality in time confirmed it. The idea of India as a democracy in a poor, unequal and diverse land was thought absurd by many observers in 1947, and the continuing elections have, imperfectly, confirmed that the idea could work.

Medicine offers another example. The germ theory of disease, advanced by Pasteur and Koch in the nineteenth century, was resisted by many physicians who preferred the theory of bad air. When the cholera bacillus was identified and sanitation based on the new theory cut deaths sharply, reality confirmed the idea. John Snow's mapping of the Broad Street pump in London in 1854, which showed that cholera cases clustered around a single water source, was an early demonstration. The idea guided the experiment, and the experiment bore it out.

Yet the relation between idea and reality is not always so happy. The history of science is also full of ideas that reality refused to confirm. The ether through which light was supposed to travel, the caloric fluid of heat and the phlogiston of burning were all ideas that failed their tests. Karl Popper stressed that a good theory is one that exposes itself to refutation, and that science progresses by eliminating errors. In this view the usual relation between reality and the idea is one of challenge and not confirmation, and the idea survives only if reality fails to contradict it.

There is also the danger that confirmation is manufactured. Psychologists speak of confirmation bias, the tendency to notice evidence that supports our beliefs and to ignore the rest. Astrology seems to be confirmed by every horoscope that comes true, and conspiracy theories absorb contrary evidence as proof of a cover up. A person with a strong idea will find reality confirming it almost anywhere, and this is no evidence at all. Reality is rich enough to supply examples for contradictory ideas, and genuine confirmation requires that the idea could have failed.

Political ideologies have suffered from this. Marxists held that history was moving toward communism, and each failure was explained away. Free market enthusiasts treated financial crises as aberrations. The attraction of an idea can lead its followers to bend reality, in the manner of those who tried to force a planned economy on a living society, and the cost was paid in famines and camps. When reality refuses to conform, an ideologue may try to make it, with disastrous results. The sentence in the topic is a warning as well as a boast, since the confidence of those who feel that reality is on their side has often preceded their worst mistakes.

The more careful reading may be that ideas and reality are in dialogue. Ideas are our attempts to grasp the world, and reality answers by confirming, correcting or rejecting them. Knowledge grows through the exchange, and an idea that has survived many such tests gains our trust. It remains an open question, and perhaps the oldest in philosophy, whether the agreement between thought and the world, when it occurs, shows that the world is rational or merely that we have learnt to see only what our thought can accommodate.