“We can always be mistaken, and one of the most important features of a successful strategy for understanding the world, is that it will constantly be testing its presuppositions, admitting the possibility of error, and trying to do better. We all want to live on a stable planet of belief, where the different parts of our world view fit together harmoniously, but we want to avoid being sucked into a black hole of belief, where our convictions are so strong that we can never escape no matter what kind of new insight or information we obtain.
You will sometimes hear the claim that even science is based on a kind of faith, for example, in the reliability in experimental data, or in the existence of unbreakable physical laws. That is wrong. As part of the practice of science, we certainly make assumptions: our sense data is giving us roughly reliable information about the world, simple explanations are preferable to complex ones, we are not brains in vats, and so forth. But we don’t have faith in those assumptions; they are components of our planets of belief, but they are always subject to revision and improvement, and even, if necessary, outright rejection. By its nature, science needs to be completely open to the actual operation of the world, and that means that we stand ready to discard any idea that is no longer useful, no matter how cherished and central it may once have seemed.”
—Sean Carroll, The Big Picture: On the Origins of Life, Meaning, and the Universe Itself
In his new book The Big Picture, Sean Carroll tells us that the facts that make up context, bits of information that we often take for granted, are called “priors.” We assess our friend’s claim about a bicyclist, a horseman, or a headless person based on priors. He goes on to explain that priors are the way that scientists can asses the results of experiments. It’s how physicists confirmed the discovery of the Higgs Boson particle, and how they discounted claims of neutrinos moving faster than the speed of light.
Throughout the book, Carroll invites readers to indulge in little thought experiments and goes on to explain how they reflect scientific experiments, concepts, debates, or philosophical conundrums. When Captain Kirk gets beamed from the USS Enterprise to another planet and his atoms are reconstituted, is that the same Kirk? If you are about to open a jar of marinara, and it suddenly occurs to you that there might be a deadly pathogen inside that will destroy humanity as soon as you open the jar, do you have to have plain spaghetti instead? What does an astronaut dropping a feather and a hammer on the moon have to do with why we should see the universe as made up of patterns and laws instead of causes and purposes?