What is it about the theory of evolution which makes it so difficult to comprehend? Why does it require a leap of faith for many people to understand? And why do they feel they need to believe in evolution in a way they never would with, say, gravity?
Having finally got around to reading The Blind Watchmaker this year, one remark really stuck in my mind, when Dawkins turned to describing the human experience in terms of units. The way we perceive the world around us is intrinsically bound to the way we encounter it. We consider time, for instance, within a fairly specific range. Once we go beyond that range, our natural, indeed evolutionary faculties are incapable of perceiving the world outside those bounds with any degree of accuracy. That’s not to say we hit a brick wall when we step beyond that range. We’re still perfectly capable of contemplating the meaning of extremely long or short timescales, for example. We can measure them, compare them, calculate them; we can analogise and use metaphors. But we are far from being able to really grok what they mean.
Take things on the shorter end of the scale. Seconds are easily counted. We’re capable of working out how long a particular journey will take us, able to estimate how much faster it will be if we’re travelling by bicycle or car. But break the second down and it soon stretches into the theoretical. The speeding bullet or the flash of lightning travel far faster than our perception allows. Sometimes we can physically sense the difference, such as when a crack of lightning reaches our eyes before our ears, but beyond that, these events exist beyond our realm of experience.
At the other end of the spectrum, most of us find it difficult to measure things even in years. When did we move house? Was it three years ago, or four? When was that holiday to Cyprus? Five years ago? Six? We usually find little memory tricks to work out the answer, supporting our assumptions with unrelated facts (‘it was the year Jane started going to school… the Olympics were on in Beijing…’) Or we end up relying on physical evidence to corroborate the facts.
Where Dawkins really hits the nail is in how we view chance. With average lifespans under 100 years, we think relatively little of crossing roads, driving cars, climbing ladders or changing light bulbs. Accidents happen, people injure themselves and even lose their lives doing such mundane activities every day. But that only ever happens to other people. The risks are small; so small that we’re willing to take them on a daily basis. Experience teaches us the difference between perceptible and theoretical risk, the difference between the overt perils of grabbing a hot pan without oven gloves and the insidious hazards of an unhealthy diet.
Yet what would happen if we were to have natural lifespans in the hundreds of thousands or even millions of years? Those relatively slim chances of being fatally injured while crossing the road would suddenly have an entirely different dimension, given the number of times you do this in a lifetime. All of those otherwise hidden dangers, the risks we acknowledge without really understanding them, would become as clear to us as those overt dangers, since most people would come a cropper before reaching the natural limits of their lifespans.
The point is that our ability to contemplate unlikely events soon passes from the sensible to senseless. We grasp the chances of tossing heads, the likelihood of a rainy day in July. But beyond a certain limit, even the little sliver of rational thought in our minds gives way to thoughtless instinct. That one in a million chance becomes indistinguishable from impossible. A typical argument used against the theory of evolution runs along the lines that scientists have been trying to recreate the origins of life in the laboratory for decades. All their best efforts have been for nought, ergo that theory cannot possibly be true. Dozens of scientists in dozens of laboratories having been trying for dozens of years to reproduce an event that happened (at least) once across billions of planets in billions of solar systems over billions of years.
The numbers are staggeringly large, making them indistinguishable from impossible. And if not downright impossible, at least so perishingly unlikely that only with blind faith could you believe it to be true?