The Atheist's Guide to Reality_ Enjoying Life Without Illusions - Alex Rosenberg [77]
Since we are going to move further and further away from common sense and ordinary beliefs about the most basic things—the things it’s hard to imagine we could be wrong about—it’s worth working out exactly why science trumps common sense. The only route to theoretical science starts with everyday experience and employs reasoning that is certified by common sense to be ironclad. At the point we have reached in our tour, science tells us that what everyday experience teaches is quite mistaken and that conscious introspection is unreliable. Since we needed both of them to get to this point, it looks like there is some sort of contradiction lurking in scientism. Looks are deceiving.
WHY SCIENCE TRUMPS COMMON SENSE, EVEN WHEN ITS CONCLUSIONS
ARE BIZARRE
Why trust science over everything else, including the human experiences we needed to build science? The usual way to answer this question begins with the technological success of science and then reflects on the general reliability of its experimental methods, as well as the self-correcting character of its institutions. That was the approach Chapter 2 employed to underwrite physics as our metaphysics, our fundamental theory of the nature of reality. This approach is right but doesn’t work very well with people who need stories and resist learning much science to begin with. There is, however, a much more convincing argument that needs to be put on the table before we really begin turning common sense upside down. It is the overwhelming reason to prefer science to ordinary beliefs, common sense, and direct experience. Science is just common sense continually improving itself, rebuilding itself, correcting itself, until it is no longer recognizable as common sense. It’s easy to miss this fact about science without studying a lot of history of science—and not the stories about science, but the succession of actual scientific theories and how common sense was both their mother and their midwife.
The history of science is in some respects like Plutarch’s story of the ship of Theseus. In the story, as each plank of the ship rotted away or mast broke or rope parted, a duplicate plank or mast or rope was made and substituted. After a certain point, the entire ship was composed of replacement parts. The philosophical question this raises is whether, after all the original parts are replaced with duplicates, Theseus’s ship is still numerically the same one he started out with. Now, imagine that instead of perfect replacements, the sailors had used their ingenuity to substitute new, improved parts on the ship. Starting with a Greek trireme galley and carried on long enough, the result could well have been a nuclear attack submarine. Whether the ship at the end of the process is the same ship as the one at the beginning we can leave to philosophers. But whether it reflects an advance in knowledge of nautical reality is not debatable. And this is the way to understand how common sense and ordinary experience become science.
Physics started with “folk physics,” a whole load of partly or mainly false beliefs about how things move. Regrettably, many of these beliefs are still with us in common sense. Yet all it takes is common sense to see that common sense about motion has to be wrong.
Most people think that to keep a ball in motion, you need to continually apply some force to it. To keep it going, you have to push it from time to time, not just on Earth but in the vacuum of space. Physics was built on this common sense. From Aristotle’s’ physics onward for 1,900 years, nonzero velocity was held to require the continual application of a force on the object in motion. It took a simple commonsense thought experiment by Galileo to refute common sense: Set a ball in motion down