Somebody attributed to Max Planck, a constant1 source of wisdom, the saying that science advances funeral by funeral. This is a pithy condensation of his more famous quotation:
A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die and a new generation grows up that is familiar with it.
Every scientist laughs along with Planck, thinking to himself how silly were those people of yore who refused to believe what was now so obvious. When scientists gather they often tell each other cautionary tales about the simpleminded stubbornness of their forefathers. Things were different then, always then. Not for a moment does it cross their minds that Planck’s wisdom could possibly apply to them.
Yet Planck was wrong: at least, if he meant that nobody ever changes his mind. Some do. But only very, very few. Einstein famously did not change his. And it is no refutation to say that perhaps Einstein will be right after all, because that would imply that Einstein’s intellectual enemies were wrong not to have changed their minds.
It is also clear that Planck had in mind foundational questions. The more a new idea conforms to whatever the current consensus in science is, the more likely it will be accepted. The new idea says, “What you believe is indeed so”, which is comforting. But the stronger a novel philosophy thumps the base of the Old Way, the more vociferous the opposition. It is saying, “You are wrong,” words few can stomach. The Wegeners and Semmelweises who arise occasionally must expect their thrashings.
Once more we have Planck:
The man who cannot occasionally imagine events and conditions of existence that are contrary to the causal principle as he knows it will never enrich his science by the addition of a new idea.
It is true that new foundational ideas are radical departures, as Planck suggests, but then so are the flood of crank theories that wash over science. An idea’s novelty is thus not an argument in its favor. To think it is is to employ what Philosopher David Stove called the Columbus argument. They did all laugh at old Christopher, and laugh wrongly, but they were right to dismiss the vast majority of novel thought.
We often hear—it is part of the standard propaganda folder—that science is self-correcting. Is it? Well, this statement is either always true, or it is always false, or somewhere in between. If we claim it is always true, we claim too much, because it is to claim all wrong ideas will always be corrected, and where is the proof for that? If you believe this, you do so on faith and in opposition to history. After all, science has at times not progressed but actively regressed. So how do we know that some of our beliefs will never be challenged successfully? It is logically possible that we hold certain ideas that are false but we can never prove false.
Then it cannot always be false that science is self-correcting, because, as is obvious, science has often progressed. So it must be somewhere in between: science often but not always and not in all places self corrects. And this says nothing about the rate at which science self corrects. For trivial, small facts, the correction is quick, as any working scientist will tell you. Yet as Planck told us, self correction is painfully, even fatally, slow for foundational ideas.
The test for regression, the opposite of self-correction, appears to be how closely aligned a science is to politics. Trofim Lysenko leaps to mind as the man who halted biology and ordered it to about face, and then marched it along the path dictated by his socialist masters. On a smaller scale, there was that infamous bill proposed (but not passed) in Indiana which would make it the law of the land that the circle could be squared (and thus the value of pi should be changed). In recent years, we have had a spate of frauds which otherwise would have been caught had the results the frauds put forth not been what their audience wanted to hear.
Science is like the branch of a tree that twists and grows in the direction of the strongest sunlight and nutrients, i.e. money. But not only that. Scientists are just people and they like to get along with others, especially colleagues. They will thus often hold an idea more strongly just because others hold it, too. Which brings us right back to Planck.