The Evidence of Things Not Seen

Nobel-Prize-Winning physicist Richard Feynman was noted for his ability to bring clarity to even the densest mysteries of the subatomic realm. But I confess I am too dense to make anything of his Nobel lecture on quantum electrodynamics or even to explain in simple English what quantum electrodynamics is. I can only pass along the anecdote Feynman said led to the breakthrough that won him the prize in 1965. He recalled having lunch in a student cafeteria at Cornell (where he was teaching at the time) when someone tossed a plate into the air. The plate was embossed with the college seal on its edge, so Feynman was able to track its rotation as the plate wobbled in the air. He could see the plate rotated and wobbled at different rates, but what was the relationship between the two? He did the math and calculated there was a two-to-one ratio of wobble to spin. He then wondered why this should be so. He did more calculations and realized they could be applied to a problem he had been puzzling over for years about the spin of electrons. Feynman later wrote, “… the whole business that I got the Nobel Prize for came from that piddling around with the wobbling plate.”

The scientific method presupposes that you are able to make careful observation and measurement of natural phenomena in order to form hypotheses and to make predictions about their future behavior based on those hypotheses. How do you proceed when the phenomena are invisible and can’t be directly measured? Einstein faced this issue in his famous 1905 paper on Brownian motion, written the same year he formulated his special theory of relativity. Brownian motion is the random movement of tiny particles suspended in a fluid medium, such as dust motes floating in the air. Einstein used statistical methods to demonstrate that the movements were the result of collisions with molecules – the first solid evidence that atoms existed.

There was nothing original about the theory that Brownian motion was caused by collisions with unseen atoms. Indeed, the Roman poet Lucretius first put forward the idea in a first-century BCE philosophical work, “On the Nature of Things.” The difference is that Einstein was able to use mathematical tools to measure precisely what otherwise could only be imagined. Feynman did the same to describe the spin of electrons, which are even smaller than atoms. He emphasized that the key to penetrating that subatomic realm was not just to be able to do the math but also to be able to imagine what was going on behind the curtain. “Our imagination is stretched to the utmost,” he wrote, “not, as in fiction, to imagine things which are not really there, but just to comprehend those things which are there.”

What exactly is being stretched when we talk about stretching the imagination? Neuroscientists point to the rapid enlargement some 300,000 years ago of the prefrontal lobes of the human brain, which control such higher cognitive functions as symbolic speech, abstract reasoning and foresight. Of most significance here is that the prefrontal lobes enable us to engage in “counterfactual thinking” – to imagine things that are not tangibly part of our immediate sensory experience, like atoms and electrons, and to make an imaginative connection to wobbling dinner plates.

Long before there were scientists, humans were hardwired to ascribe invisible causes to visible effects. For example, a flood or famine might indicate the gods were angry with them. The Old Testament provides numerous examples of this, starting with the story of the Plagues of Egypt. According to the account in the Book of Exodus, the pharaoh refused to allow Moses to lead the Hebrew slaves out of Egypt, so the Lord visited a series of ten plagues upon the hapless Egyptians. These included various types of disease and pestilence, a hailstorm, three days of darkness and ultimately the death of all the first-born children and animals in Egypt, after which the pharaoh relented and allowed the Hebrews to leave. There is no surviving historical account of these events apart from the Book of Exodus itself, so we don’t know what the factual basis was, if any, for the plagues.

In time of famine or plague during the Middle Ages, flagellants would wander from town to town, whipping themselves to atone for the sins they believed had brought such misfortune upon them. If something bad happened and there was no obvious explanation, then God must be punishing them. It was either that or the Jews, who were accused on poisoning wells during the Black Death and who were murdered by the thousands

In discussing the role of imagination in scientific discovery, Feynman made an important distinction between imagining things that aren’t really there, as in fiction, and those that are. Since we are talking here about things that are invisible and may otherwise be detectable only indirectly, it is not immediately clear what might be actually be there and what might not. Fiction, of course, may be about real things, but they have not actually happened. And the history of science is replete with theories that were once thought to be true but turned out to be wrong. For example, Einstein’s special theory of relativity overturned many of Isaac Newton’s cherished assumptions about time and space, including the belief that the universe was pervaded by an invisible and undetectable substance called aether that was needed to transmit light through space. It turned out the stuff was invisible and undetectable because it didn’t exist. Currently, astrophysicists theorize that as much as 90% of the universe is made up of so-called dark matter that, like aether, is invisible and undetectable – at least for now. Dark matter plugs a hole in our understanding of the universe, but does it actually exist? Stay tuned.

What role does imagination play in spiritual matters? Adherents of science might claim that religion is entirely a product of the imagination. Yet, as we have seen, imagination is often allowed much freer rein in science than in religion, which tends to get mired in dogma. Just where we would be if Newton’s Principia were regarded as a sacred text, or scientists were accused of heresy for declaring the earth revolved around the sun? As a matter of fact, scientists were accused of heresy for insisting the earth revolved around the sun – only the accusers were the religious authorities.

The difference between science and religion is that scientific truths must be falsifiable – that is to say, there must be some way they can conceivably be proven wrong. By contrast, religious propositions can never be proven wrong – or right – even if they are true. There are no mathematical tools that will enable you to penetrate the spiritual realm. All you have really is imagination, that mysterious by-product of human evolution that showed up nearly 300,000 years before anyone could do the math. That’s 300,000 years of ascribing invisible causes to visible effects, and often getting things horribly wrong. But without our powers of imagination, without our ability to see behind the curtain, there would be no revelation.

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