When science is inconvenient and we want to disregard its conclusions, we tend to rely on the old axiom that science doesn’t prove anything. And it’s true. But science does tell us what has the highest probability of being true at any given time, and therein lies its power.
We think our giant brains are such an asset to us. But in this age of fake news and social media bubbles, it’s easy to see how our brains might actually be a liability. After all, we can delude ourselves quite as fast as we can dream up useful explanations for observed phenomena. Maybe even faster.
Despite our ability to delude ourselves, humans have a variety of mechanisms through which we profess to acquire truth, some of which include science, philosophy, religion, reason, experience, intuition, and even love. Unfortunately, every single one of those truth-discovery tools shares at least one common defect: They all require the human lens. But sadly, humans are irredeemably biased.
This brings us to Harari’s book, the subject of this inaugural post on my new medical science blog. In his sweeping account of the human species, history professor Yuval Harari makes the case that four major historical turning points brought our species to this pivotal moment in time — which is at the precipice of either utter world annihilation, or complete and total mastery of the universe. (The jury is still out on which of those two options it will be, but I’m betting that you have an opinion. Click here to tell me what it is.)
Oddly, his take on the scientific revolution 1,500 years ago isn’t even the most interesting thing to discuss in this science blog. Rather, I want to talk about his take on the cognitive revolution, which started about 70,000 years ago, because that was when our species first developed the capacity for self-delusion. According to Harari, the cognitive revolution began when our species developed the capacity for imagination, thanks to an evolutionary change in brain size. Among other things, this change gave us the capacity to convince ourselves (and others) to believe in complete fictions. You might even be surprised to learn (as I was) that modern humans actually believe in a startling number of fictions. Incredibly, most of the things that we build our lives on — things we take for granted as objective truths — are actually fictions, or at best subjective truths.
Harari defines a subjective truth as something that is only “true” because most people believe in it. The dollar, democracy, the free market, the US government, human rights, and justice — all things that are foundational to our way of life — would cease to be if people suddenly quit believing in them. Harari illustrated this by explaining the origins of the French automobile manufacturer Peugeot: The company doesn’t really exist, he says, at least not in the sense that there is a set of objects that comprises it. Rather, Peugeot is a subjective reality that came into being when a few Parisian lawyers wrote the right magic words into its articles of incorporation. After that bit of hocus-pocus, people suddenly started showing up — bringing raw materials, assembling engines, and buying and selling cars.
Sounds magical, doesn’t it?
When you understand that the very validity of our most beloved values and institutions requires shared belief, the idea of subjective truths can be rather disorienting — especially in this cultural moment of extreme disunity. Is climate change real? Do vaccines cause autism? Does Trump lie? Is the deep state a thing? When you read Sapiens you may begin to question — as I did in a momentary pang of existential uncertainty — whether anything you ever believed is even knowable at all.
Consider the truth-acquisition tools above. Which of these objectively exists outside of the human mind? Not a single one. No, not even science is real in this sense. It’s a philosophy. A set of methods. A process. It’s a deeply creative practice — perhaps even approaching the mystical — by which we can make imagined things real.
Let me explain:
Consider John Snow, an anesthesiologist in nineteenth-century London. He lived and worked at a time when speedy ship travel could pick up newly-infected cholera patients in one exotic locale and deliver them to England with just enough survival time to infect unsuspecting Londoners. At the time, most people believed that cholera was caused by “bad air,” but John Snow — something of a prophet, poet, or magician — imagined something different. And then he made it so. A full decade before the microscope was invented, and at least a half-century before germ theory emerged, Snow invented the idea of microscopic disease-causing particles producing a deadly diarrhea, and contaminating the water supply.
He simply imagined it.
When Snow was dreaming all of this up, it was a complete fiction — an idea that existed in his mind and nowhere else. But the idea endowed Snow with immense power — to stop cholera epidemics. Years later humans learned to visualize, empirically measure, and selectively destroy the disease-causing pathogen Vibrio cholerae, at which time it ceased to be a fiction and it became an objective truth. But it’s not unfair to say it was a truth brought into existence by a powerful “bacteriomancer” named John Snow. It’s as if he said, “Let there be water-borne, microscopic disease pathogens,” and they appeared.
This “powerful fiction” phenomenon is not an anomaly. This is how all hypotheses start! We have many modern science fictions that are not yet alchemically transformed into truths. For instance, we still can’t see the nucleus of atoms, but our model for atomic orbitals is a fiction that correlates so well with chemical behavior that modern organic chemists are like masterful wizards, manipulating the very elements!
Science is the only one of our truth-acquisition tools that consistently enables the human collective to make reliable progress toward eliminating human delusion. I believe that this is true even though scientists are not any less biased than the rest of us. You see, disagreement about shared subjective realities is as much a problem in science as anywhere else. Just consider these scientists fighting over how to sample vaccine evidence. It’s a fight between two factions within Cochrane, the ivory tower of medical evidence synthesis.
Despite that lack of dispassionate objectivity, here’s what’s cool about science: While the feminists will likely never see eye-to-eye with the men’s rights activists, the Fox News viewers will never agree with New York Times readers, and the atheists will never achieve consensus with the monotheists, we can all rest assured that the Cochrane blowout is going to work itself out. Why? Because at the heart of its meta-physics, science has a secret weapon. Unlike most other fictional realities, it is powered by an empirically measurable force that no self-respecting practitioner of science will ever disregard. What other belief system can say the same?
What is this mystical force that enables practitioners of the science cult to discover truth? We call it probability. If it sounds implausible that probability is a source of power potent enough to move mountains, consider Las Vegas, a sprawling city in the middle of a desert. If this overgrown city doesn’t persuade you that probability is a powerful force, then odds are that you’ve never played a game of chance. In Las Vegas, the house always bets on probability, and it always wins. I mean, it’s true that once in a while luck smiles on some hapless soul who happens to place a bet on the table where lightning is about to strike. But at the end of the night, who is raking in the most chips? The house.
You know who else? Science. Because science always bets on probability too.
Just like casinos, science doesn’t win every bet, of course. Sometimes science is wrong — for a number of reasons. Sometimes it’s because of human bias, or because we fail to publish our least interesting results. Sometimes it’s because of fraudsters attempting to deceive us, or because we can’t strictly adhere to the best practices of science. Sometimes it’s even just because a butterfly flapped its wings. But as long as we keep at it, science is self-correcting. Eventually, the things with the highest probability of being true will always rise to the top.
Granted, that’s not the same thing as science just telling us what’s true. As any first-semester science student will emphatically tell you, science doesn’t prove things. It’s more cryptic than that. Science only tells us the probability that a particular hypothesis is false within the specific context of a single experiment. This probability — the mystical P-value — is more accurate if we’ve strictly adhered to the requirements of the experimental rites. But even if we make errors, as time marches on, and with the repeated application of the scientific method, our misconceptions dissipate, and eventually truth is revealed.
At a time when most belief systems are losing adherents, science still claims the devotion of millions of practicing believers — including me, despite its reliance on feeble human brains. Personally, I consider myself a disciple to science. I tithe to it. I sing it hymns of praise. I revere its dogmas, and I preach them to my students year after year. I’ve given my life to it. I have to. It’s a powerful subjective truth that has consistently brought goodness to humankind, and it will continue to do so only as long as we believe in it enough to fund it, to adhere to its rituals, and to act on the knowledge it gives us.