It’s just come out that what scientists believed to hold true about the nature of the neutron wasn’t true. Before recent discoveries showed otherwise, they held that the neutron consisted of a particle with a negatively-charged shell and a positively-charged core. Now it is known that the neutron consists of a negative shell and a negative core with a positive layer between. Enrico Fermi was wrong.
Does this mean that particle physics is going to collapse? Is it a defeat for science? No.
“Nobody realized this was the case,” Miller said. “It is significant because it is a clear fact of nature that we didn’t know before. Now we know it.”
The discovery changes scientific understanding of how neutrons interact with negatively charged electrons and positively charged protons. Specifically, it has implications for understanding the strong force, one of the four fundamental forces of nature (the others are the weak force, electromagnetism and gravity).
The strong force binds atomic nuclei together, which makes it possible for atoms, the building blocks of all matter, to assemble into molecules.
“We have to understand exactly how the strong force works, because it is the strongest force we know in the universe,” Miller said.
This goes back to what I said the other day about belief. Since 1947, physicists have believed in one version of the construction of the neutron. Now with new evidence, the smartest among them must adopt another, better version. They’ve come a long ways from [[Democritus]] who held that atoms were the smallest, indivisible unit of matter and will undoubtably go farther. That the knowledge brings them closer to the truth does not make it any less a belief: we cannot be certain that future discoveries will not cause yet another revision. For now, based on the evidence, this is the best model we have and it is probably better than the ones which have come before.
Everything we advance as a scientific principle must, because we are not omniscient, be held as tentative. We do not come born with the knowledge in our bones and we cannot obtain it instantly, by stretching our awareness into all places. Our existence is a little like [[Zeno_of_Elea|Zeno’s]] fable of Achilles and the tortoise. The tortoise — which might be called the truth — has a mile headstart. Achilles must catch up and pass the tortoise to win. Yet to get there, he must first get halfway there. And once he has accomplished this, he must move halfway yet again. Because there are an infinite number of halves to traverse, he cannot cover the mile. In the meantime, the tortoise has moved a little farther.
This does not work for the natural world, of course, but it may serve as an apt metaphor for Science. Our understandings take us closer to the truth, but there is always a gap to be covered halfway. So we go on, developing better and better models. We hold them as the best thing and, if Science has done its job as it has in the case of evolution, it serves as a better explanation than what has been said before. We believe our current models to be satisfactory enough to get us through the general problems of understanding the Universe. We live with uncertainty, however, and in that sense Science must be considered to be an aggregate of beliefs that do a better job of explaining than others.
As the story of the neutron shows, what we believe we know will, in some ways, change. That is where we can draw the division between dogma and Science: the beliefs of the former strive to remain unaltered while the second remain subject to new discoveries. It does not allow us to become stuck in erroneous views except by willfullness.
Belief helps us get by until we get a better belief. It pays to follow the tortoise.