What are the Strongest Scientific Consensuses That Turned Out to Be Possibly, or Definitely, Wrong?

Yes of course. It is a good bet. But the track record is very mixed. That’s kind of the point of this entire thread. We shouldn’t be gambling with these things.

Did crustal displacement or the expanding earth have any degree of general acceptance?

One idea that I notice is being alluded to in this thread is that the since the consensus has sometimes been wrong scientific consensuses can’t be trusted - and I completely disagree with that. The consensus is sometimes wrong, but it always has a large amount of evidence and experience behind it, and it’s sensible to take the consensus as a starting point because it’s very likely to be true. A few times a century - if that often - someone who is very well-versed in the current consensus can find a way to move beyond it or transform it - and when that happens, generally a very large percentage of observations still fit the old consensus very well, even as scientists discover ways to find the tiny observational differences between the old and the new. In 1900, the consensus was the transforming one element to another was strictly impossible, but by a few decades later, it was discovered to be merely very very difficult, and required vast amounts of effort to make the tiniest amount of elemental change. In day-to-day life, transformation of the elements is still practically impossible and the advice a physicist from 1900 would give you (“Hey, that guy offering you an elixir to convert lead to gold is a fraud”) is stll right.

Now “engineering consensus” (which I think this is), is often very wrong indeed, because engineers get a very good idea of what’s possible with current technology, and that can make it hard for them to imagine applications to something newly discovered (hey, I’m an engineer, I can say that).

Cite?

This thread hasn’t really shown that many examples of such, nor any gambles based on it, either. Certainly not the ozone hole, nor acid rain

Maybe the thread hasn’t. Sorry not everyone can meet these exacting specifications.

It was perhaps not a consensus, nor was it perhaps even likely. But it was at least for a time considered a possibility that an atomic bomb would ignite the earth’s atmosphere. And they just didn’t know for sure. Probably not. Most likely, not. But they set it off anyway, didn’t they?

This is supposed to be FQ and the thread is about consensuses. And that’s an example of a consensus that did not exist.

As for setting the bomb off, this makes it sound like there was no idea of the likelihood or that the test was performed with cavalier disregard for safety. Study the math and the history. The speculation itself led to Project scientists studying the problem and coming up with the numbers. The chances were determined to be negligible - worse than lottery chances.

No. They considered the possibility, did the calculations, correctly determined that igniting the atmosphere was impossible and then tested the bomb

Horgan: I wonder if you could tell me a little bit about the story of Teller’s suggestion that the atomic bomb might ignite the atmosphere around the Earth.

Bethe: It is such absolute nonsense [laughter]… One day at Berkeley, Teller came to the office and said, “Well, what would happen to the air if an atomic [fission] bomb were exploded in the air?” The original idea about the hydrogen [fusion] bomb was that one would explode an atomic bomb and then simply the heat from the atomic bomb would ignite a large vessel of deuterium… and make it react. So Teller said, “Well, how about the air? There’s nitrogen in the air, and you can have a nuclear reaction in which two nitrogen nuclei collide and become oxygen plus carbon, and in this process you set free a lot of energy. Couldn’t that happen?”…

Oppenheimer [soon to be appointed head of Los Alamos Laboratory] got quite excited and said, “That’s a terrible possibility.” And he went to his superior, who was Arthur Compton [director of the Chicago arm of the Manhattan Project], and told him that. Well, I sat down and looked at the problem, about whether two nitrogen nuclei could penetrate each other and make that nuclear reaction, and I found that it was just incredibly unlikely. And I said so, and I think Teller was very quickly convinced, and so was Oppenheimer when he’d returned from seeing Compton…[Later, Emil Konopinski and another physicist showed that it was impossible]

Yeah, there really was not true consensus on either subject. A Doctor might say, “Well, we are not sure exactly what causes ulcers- but we do know that stress and lifestyle makes them flare up”.

The Miasma Hypothesis was really before medicine was a true science.

Right, scientists would say “Technically we are still in the end of the last Ice age.”

Well, one of his guesses was 24000 miles, which is damned close. But what he really thought was that Asia stuck way way out further than it really did- and since no European really knew better, that sounded reasonable. (To be honest we really do not know exactly how big Columbus thought the world was- none of his writings confirm any of those figures. But he did say he could reach Asia by going West.)

Definitely some of the examples here are things I would not have called consensus.

It is healthy and productive for a field to have working theories about how things may work. This provides a framework for research progress, allowing poking around the edges of a given working theory or theories. In some cases, these working theories may be nearly universally accepted for what they are, but there remains a gap between that and being a consensus about How Things Really Work. A “best guess so far” is rather different from “solid evidence that this is so”. And this important gap is one of the many nuances left out in public communication, since nuance is boring to non-experts. (“Gimme news and conclusions!”)

Things that are discovered out of left field naturally engender skepticism. That’s important and healthy. But such resistance doesn’t mean there is a consensus that the new thing is wrong. In fact, intense work to figure out which side’s perspective holds up is evidence that there wasn’t a consensus view.

Relatedly, many things that come out of left field don’t automatically inherit a retroactive consensus view that they “couldn’t have been”. Often, the new thing just wasn’t even pondered one way or another because there wasn’t any need (yet). Occam’s razor explains the prior view.

That wasn’t a guess - that was close to the the actual scientific consensus at the time based on calculations from centuries earlier. But Columbus didn’t use that number - he used the much smaller number that would justify his trip westward.

http://www.phy6.org/stargaze/Scolumb.htm

Even my example of Luminiferous aether was by no means a consensus.

The aether hypothesis was the topic of considerable debate throughout its history, as it required the existence of an invisible and infinite material with no interaction with physical objects. As the nature of light was explored, especially in the 19th century, the physical qualities required of an aether became increasingly contradictory. By the late 19th century, the existence of the aether was being questioned, although there was no physical theory to replace it.

Basically it was “our best guess hypothesis, which seems to match current data”.

Right. In fact i can not think of anytime a proven theory was shown to be dead wrong. Lots of best guesses, hypothesis, ideas, etc.

I’ve studied the history extensively, or at least more than most. This is why I brought it up. I didn’t suggest it was “cavalier”, those are your words, not mine. The chances were determined to be “negligible”, but let’s hope they didn’t drop a decimal, right? It was still a question …

But did really believe that or did he really think Asia was just a whole lot closer? We can not see anything from Columbus writings that he believed the earth was much smaller. It is hard to tell what his actual beliefs were- other than he was dead sure he could (and did, he never gave up that he had landed in parts of Asia) get to outlying parts of Asia by sailing west

The nature of light might be a good example. Newton argued that light was a particle based on the sharpness of shadows and similar evidence.

Thomas Young then proved that light was a wave based on the knock-down argument that his double-slit experiment could not be explained by anything but waves.

Amusingly both were wrong. Light is something that can’t be explained as an ordinary particle or an ordinary wave

In modern physics, the double-slit experiment demonstrates that light and matter can exhibit behavior associated with both classical particles and classical waves.

What Young proved was that light could also act as a wave. But Newton did not prove his theory.- it just fit the current known facts.

I think he believed it - after all, he was planning a trip not to Asia in general, but to India - a place that was reasonably well explored by Westerners by that time, and Columbia believed that the North American islands he found were Japan, not some part of a far-extended Asia

Young’s double-slit experiment was different than the modern experiment - Young could see diffraction (a wave phenomenon) but couldn’t see individual photon interactions

Do his writings say so? They say he was seeking a western ROUTE to the spices, etc of the East.

As noted above, later on some scientists determined it was actually impossible, not just unlikely.

But even they dropped a decimal place or three on their initial work, the odds would still have been negligible, unlike, say, lottery odds.

I’m not even sure what this example is supposed to show. It doesn’t show what was claimed, nor was it something later shown to be wrong despite a strong consensus at the time.

No, the idea of a coming Ice Age was never taken seriously by most scientists, not dismissed by some semantic technicality.

Did I say it was? I remember that line from my textbooks. That does not mean that another ice Age is coming soon.

https://pressbooks.nvcc.edu/eng255/chapter/the-journals-of-christopher-columbus-during-his-first-voyage-1492-1493/

They found land on Thursday, 11th of October, and on Wednesday, 24th of October Columbus writes:

At midnight I weighed the anchors and left the anchorage at Cabo del Isleo, in the island of Isabella. From the northern side, where I was, I intended to go to the island of Cuba, where I heard of the people who were very great, and had gold, spices, merchandise, and large ships. They showed me that the course thither would be W.S.W., and so I hold. For I believe that it is so, as all the Indians of these islands, as well as those I brought with me in the ships, told me by signs. I cannot understand their language, but I believe that it is of the island of Cipango that they recount these wonders.

Cipango is the name Europeans used for Japan, so Columbus has traveled far enough to hear word of Cuba and believes that that must be Japan. So he’s way off on the size of the Earth.