Warning: This blog is written for a rational audience that likes to have fun wrestling with unique or controversial points of view. It is written in a style that can easily be confused as advocacy for one sort of unpleasantness or another. It is not intended to change anyone's beliefs or actions. If you quote from this post or link to it, which you are welcome to do, please take responsibility for whatever happens if you mismatch the audience and the content.


Let's get this out of the way first...

In the realm of science, a theory is an idea that is so strongly supported by data and prediction that it might as well be called a fact. But in common conversation among non-scientists, "theory" means almost the opposite. To the non-scientist, calling something a theory means you don't have enough data to confirm it.

I'll be talking about the scientific definition of a theory in this post. And I have one question that I have seen asked many times (unsuccessfully) on the Internet: How often are scientific theories overturned in favor of new and better theories?

I assume Creationists are the ones usually asking the question. And if history is our guide, the comments on this blog will focus on that one area and destroy the value of this blog post. I'm hoping we can ignore evolution and creationism and climate change for one day and just ask the following question: How often does a scientific theory get discarded or replaced with a better one?

I don't think there's a good answer to my question, for lots of reasons.

For starters, I doubt anyone has been keeping a stat on overturned theories. And I don't think it's fair to compare theories from a hundred years ago to theories created today because our ability to collect confirming data today is better than it used to be. I would expect that a theory created recently would be more likely to stand than one created last century.

Still, it has always been true that the stuff we believe today looks way smarter than the dumbass things our grandparents believed. Why wouldn't that be just as true for our future great-grandkids looking back at our primitive beliefs? Some humility is always called for.

Science requires credibility to be useful. And that's a problem. The non-scientist asks "What is your success rate?" and gets no useful answer. Scientists, as it turns out, are terrible at marketing. About 90% of my exposure to science involves media reports that get correlation and causation confused. As a result of that exposure, the more I hear about science, the less credible it feels.

To make matters worse, I have a jaded Dilbert mindset about every industry. Unless science is different from all other human endeavors, 10% of scientists are honest and amazing and doing important science while the other 90% are like Dilbert's worthless co-workers. So when I hear that 98% of scientists are on the same side of an issue, I wonder how many unreliable people you have to add together to get an opinion you can trust.

I don't think I'm alone in my views. I'll bet that if you did a poll you'd find that scientists believe theories are fairly dependable and useful whereas the average non-scientist believes that everything we think we know today eventually gets disproved. Part of the problem is that scientists are looking at utility and non-scientists are looking at "truth" which is a fuzzy and overrated concept.

In every other field, your track record of success determines your credibility. Personally, I have no idea what the track record of science is. All I know are anecdotes about wonderful successes and notable mistakes. I don't even have a general sense of whether scientific theories have usually held up over time or not.

So when scientists say a particular theory is backed by the majority of scientists, how much weight should I put on that? Is that a situation in which I can depend on the scientists to be right 95% of the time or 5%? What's the track record?

Note to the Bearded Taint's Worshippers: Evolution is a scientific fact. Climate change is a scientific fact. When you quote me out of context - and you will - this is the paragraph you want to leave out to justify your confused outrage.


Scott Adams

Co-founder of CalendarTree.com

Author of a book on success. (Makes a good graduation gift, btw)


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Apr 14, 2014
How could you ever trust a consensus of scientists if they are merely an illusion in the same hologram that makes you think your "reality" really exists? Which is controlled by the robots. Or something.
Apr 14, 2014
@Batsinthebelfry: Can you provide a source for that, or at least some key words I can Google? Googling general terms hasn't turned up anything for me, and anecdotally, I know that Drake came up with his equation in 1961 (which speculated that there was plenty of life out there). Most stuff I've read about the topic indicates scientists have been pretty optimistic about the existence of extraterrestrial life (I don't know about intelligent life specifically, but I've never seen it denied). Don't confuse what people with a little education and a lot of ego repeat with scientific theory.
+6 Rank Up Rank Down
Apr 14, 2014
I trust science but not scientists. I trust science less when politicians get involved. Mainly because I think politics is less about science and more about corruption. So when I see politicians lining up behind something scientific or otherwise I start questioning the validity of the scientists and their work.
Apr 14, 2014
@Phantom II:
1. I would point out that Lemaitre didn’t use the Bible for his work, he found one solution to the equations of General Relativity.
2. Lemaitre’s work was not laughed at, it was not read at all, since it was in an obscure journal. There was no data to clearly support it at that time, either.
3. Evolution theory does not have to explain where life came from, only how it developed. This is why it can accommodate Panspermia.
4. There are literally thousands of transitional fossils. Some, like Tiktaalik, were even predicted before they were found.
5. Six-day creation is not a theory at all in the scientific sense. Any predictions that have been made using it have been shown to be false.
6. Continue with the arguments that you have when you have actual physical evidence to discuss, if you want to be taken seriously.
+9 Rank Up Rank Down
Apr 14, 2014

From my untrained and unscientific and uneducated little mind...

Trying to understand the universe is like hitting an irrational number. You might get closer, but you are not, ever, going to get there. One never gets to big 'F' Fact or big 'T' Truth. One continues the struggle to come as close as one can.

It's called a theory because real scientists are not so presumptuous that they think they have achieved Truth. One piece of currently unknown evidence may change everything, and it could be just over the horizon. So it's a Theory, not Truth.

Facts, how many bones in the human body, how many planets in the solar system, are not in the same class as the Theory of Relativity or the Theory of Evolution. There are too many pieces of the puzzle to declare Theories as Fact. (But with my life, I'll trust an engineer's guess over a politician's fact any day.)

Hypothesis is: 'This sounds right, is this right?'
Theory is tested, repeatable, verifiable. With the information and skills we have right now, it's as close to describing the truth as we are going to get.

Evolution is the best Theory we have so far. If aliens come down tomorrow with similar DNA, we then change the theory. Humans Causing Global Warming is not Fact nor a Theory. It's at best multiple working hypotheses.

You should hear the crazy talk in the woods about Common Core. I blame the lack of teaching scientific methods to everyone.

...Wait, Pluto isn't a planet anymore? I guess you can change facts to fit your point of view, if you change the definitions. Fine, just keep your hands out of my pocket while you do it.

+5 Rank Up Rank Down
Apr 14, 2014
@Phantom II
"Some would note the fact (there's one for you, Scott) that the Earth's climate hasn't had statistically significant warming for the past 17 years (even East Anglia's Phil Jones admits that) should make true believers question their position. But no."
Statistically, if the earth was warming at the rate that scientists see it warming, there should be at least one decade this century when the pattern seems to stop or even cool.
That said, why are so many folks suddenly interested in the Arctic ocean, for the last 400 years it has been frozen solid and impossible to use for navigation (other than by submarines) or drilling.
If global warming is a hoax, the recent massive thawing of this area is a historical fluke, which should correct itself shortly, right?
BTW, everyone on all sides of the debate should read XKCD's what if here:
Modeling this stuff is no easy task...
+2 Rank Up Rank Down
Apr 14, 2014
Simple idea, judge theories by usefulness...
Newtonian physics is a dis-proven theory. However, for most practical engineering, it works pretty well. In fact, the correction from Newtonian physics to Einsteinian physics for the GPS system was originally rejected by the engineers who built the system (only to be turned on in a matter of hours as the clocks in the satellites rapidly went out of sync with earth, leading to massive position errors).
Ask a climate change scientist when he isn't talking for the cameras about his/her certainty, and he/she would say "I am dealing with huge ranges of probability here, all I can say for sure is that it meets the 95% confidence level of occurring and being human caused, meaning that there is a 1 in 20 chance I am wrong about one or both of these statements."
That said, if there is a 95% chance the earth is getting warmer, and the projections of "how much warmer" are also at the 95% confidence level, well, the 50% confidence level (what we would actually expect) is a LOT WARMER!
This is why the folks against it keep having to shift their positions (from "it isn't happening," to "It isn't man-made" to "It isn't that bad."), it is so much worse than what we are being told precisely because there are so many folks who think it isn't real, that the folks who actually know have to be ultra-conservative. This only emboldens the folks who want to say it isn't real because Exxon said so, which leads those folks to make statements that seem silly a year later.
On one side, folks who are sure it is bad, but can't say how bad because if they ever overstate their case, they will be called liars even worse then they already are, on the other side, liars who don't care how bad it is, as long as they can hold off the truth for another quarter and keep making money off their stocks.
+23 Rank Up Rank Down
Apr 14, 2014
If your opinions and hypothesis NEVER change, you aren't a scientist.
New data either reinforces your existing hypothesis or warrants that it be tweaked to allow for the new data.

That's how the process and science works, so evolving hypothesis are a given.

I don't think it's important that hypothesis change, or how often they change.
All that's important is remaining open to the possibility of change.
Apr 14, 2014
I am not one of the Bearded Taint's followers, Scott, but you're wrong on both counts. The theory of evolution is a theory. The theory of man-caused climate change is a theory.

Of the two, there is much more evidence for evolution than there is for man-caused climate change. But both theories are still just that - theories. You believe that both theories are fact because that better fits your worldview.

Obviously, something or somebody ticked you off concerning your pet theories, and that led you to write this rant. Get over it.

My theory is that other people writing here have pointed out some of the big errors scientific consensus has given us. But, as you know, I don't read other responses before I write mine. But here's one to consider: (a) who was the first person to propose the Big Bang theory, and place it at approximately 14 billion years ago, and (b) what was the consensus response to his theory from the scientific community?

Answers: (a) Belgian Catholic priest Georges LeMaitre in 1927. (b) He was generally laughed at by the scientific community of the time because his theory sounded too much like the biblical book of Genesis' 'Let there be light.'

Both religion and science are searches for truth. Sometimes they go in opposite directions, but often can find common ground. The problem arises when one community or the other begins to dismiss the other side's ideas out of hand.

The theory of evolution is incomplete. There are many questions it can't answer, such as: how did life first begin; where is the fossil record for transition species; mathematically, not enough time has passed for the generations necessary to produce humanity from the normal mutation process. That doesn't mean creationism (as in six days) is a better theory. It just means that evolution is still just a theory until the big problems it still has can be answered. You proclaiming it fact does not make it so.

Man-caused climate change is another theory that has even less evidence to support it. Yet people who are 'believers' refuse to question it, even going so far as proposing that those who don't believe in it should be thrown in jail.

Shades of the Inquisition. How enlightened.

Some would note the fact (there's one for you, Scott) that the Earth's climate hasn't had statistically significant warming for the past 17 years (even East Anglia's Phil Jones admits that) should make true believers question their position. But no.

Or maybe noting that physicist Freeman Dyson, whom many believe is the smartest man alive (he calculated the number of atoms in the sun when he was five years old), says that increased CO2 may be good for the planet. As Dyson says, "Science of course is always correcting mistakes. That's what it's all about." What it's not about is consensus.

I'd suggest, Scott, that you read Paul Mulshine's article (he's not a conservative, by the way) titled, "'Consensus': Is Carbon Dioxide the New Cholesterol?" In it he points out another huge area where scientific consensus led to an erroneous conclusion: the effect of saturated fats in raising cholesterol levels. For anyone with an open mind, it's an eye-opener.

Consensus does not create fact. Theory is not fact. Facts are observable; theories attempt to take observations and create reasons for why they happen. They're not always right.

The big problem with climate change 'science' is that there's too much money wrapped up in keeping the theory going, even in light of the growing evidence against it. As I've noted here before, Scott, you should read the late Dr. Michael Crichton's speech-turned-article titled 'Aliens cause global warming."In it, he proposes that there is too much politics in science, and there should be a type of double-blind study methodology adopted to remove political and financial bias from the process.

Both articles are enlightening. Both should make you at least rethink your beliefs. But there's no chance that they will. You are a true believer in climate change; you believe in it as zealously as any religious person ever believed in God.

While I know nothing can shake your faith, I still had to try. Good luck clinging to your theories. And please don't try to say that those of us who don't accept the theories you blindly accept as fact are somehow deniers of the truth.
0 Rank Up Rank Down
Apr 14, 2014
G.E.P Box: "All models are wrong, but some are useful". Our scientific understanding is a collection of models, and as such they're all wrong. But a lot are useful, and theories being disproved doesn't make them less useful. Most of the time, we narrow in on things, rather than start facing some other way.

Example: some Greek folks calculated the radius of the Earth, and they were demonstrably wrong by some amount. We now know that radius with more precision, but we're still wrong. You could say we're "less wrong": it's a matter of degrees. But if you want to plan a trip around the Earth, you'll quickly find out from looking at the "wrong" number that walking it is probably not the best way to go. Saying "oh, I'm going to risk the walk 'cuz these scientist folks are always wrong" is taking the word "wrong" and taking it to extreme and ridiculous consequences.

We thought time was absolute. That's wrong. But for most things that you want to do on Earth, like building a bridge, or a car, or throwing a baseball, or generating electricity, time is *close enough* to being absolute that you don't need to worry about it. That doesn't discount the usefulness of Newtonian physics. And if you think you'll be able to jump off a building and survive because Newton put a constant where he should've put a variable, reality is going to smash against you in a manner totally indistinguishable from how it would've crushed you if Newton had gotten everything absolutely right.

This makes science reliable even if it's wrong in some way. It's more often the case that we're missing parts of the picture, rather than that we're staring at the wrong picture. And we've gotten a lot better at applying science to science, i.e. knowing the degree of error that we're subject to.

It's easy to say "theories are always wrong", forgetting that on the flip side, prevalent theories are the one explanation we know about that is "the closest to being true".

+5 Rank Up Rank Down
Apr 14, 2014
It's too simplistic to talk about proved/disproved.

Feels like you were onto something when you talk about truth being "fuzzy". Science is about disproving things and showing them to be wrong, but paradoxically that is also where the process creates value.

Theories are usually refined, not overturned outright. "Disproving" a theory may be about finding the 2 cases in a million where it doesn't apply. Theories evolve over time, adding qualifications, special cases and additional details. Obviously sometimes something comes along that totally throws out the old worldview, but I don't think it's the norm.

To an extent scientific theories are like building models in Economics. You are trying to find a workable version of the truth that tells you something, not reproduce every facet of reality.
Apr 14, 2014
Scott, Apologies if I misunderstood your post, but thought this might help. Have you seen "The Half-life of Facts"? Came out about 18 months ago and discusses how frequently do established "facts" change. A thoughtful analysis that is not always an easy read, but was definitely overall enjoyable. (I am not the author!)

Apr 14, 2014
Up until about 20 years ago it was pretty well accepted within the scientific community that we were the only intelligent species in the universe. It was accepted that the chances of life occurring anywhere were so minuscule that its was reasonable to say that it only happened one time and that was here on earth. Now its fashionable to say that though life most likely exists throughout the cosmos there is virtually no way any other intelligent life could travel over the vast cosmic distances to get to our world and further more, why would any intelligent species bother to come all that way to this little insignificant planet out in the middle of no where. I hope I live long enough to see them eat those words also.
+1 Rank Up Rank Down
Apr 14, 2014
Lay people don't really understand science and don't know the difference between science and technology or engineering. Science holds that any hypothesis that doesn't make good predictions should be discarded. Our structures, our bridges, our technology are the evidence that theories work.

People don't understand the concept of science because of the way the media reports on science. For example, "fat is bad and carbs are good", oops, we meant "carbs are bad and veggies are good". For years we heard the former and it resulted in an overweight diabetic population.

So of course people have become suspicious of scientific claims and the media is complicit here because they just print what some scientist says without question.
Apr 14, 2014
"We can say that a theory is wrong, however, if it makes no useful and verifiable predictions."

Or, even worse, "not even wrong!"

Apr 14, 2014
Scientific theories are either useful or not useful, as opposed to true or false. Quantum mechanics is useful because it make predictions that can be confirmed within the limits of attainable precision (e.g. if a build a transistor it will work.) Evolution is useful because it makes predictions that can be confirmed(e.g. if I genetically modify a crop to poison an insect, that insect will evolve to be resistant to the poison, or go extinct). Newtonian gravity is useful because it predicts how some objects behave "closely enough". Einstein's gravity is better in fields that it can be applied to because it makes better predictions - but at its heart it conflicts with quantum mechanics. One day a theory may emerge to reconcile them. All physics is "wrong" in the sense that current theories have lost most of the matter/energy in the universe. Merely calling the missing elements "dark matter" and "dark energy" is about as useful as calling it "God".

In no sense is any of those theories "correct". It is not even clear how a theory of the physical world can be correct in the same sense that a mathematical proof is correct. We can say that a theory is wrong, however, if it makes no useful and verifiable predictions.
Apr 14, 2014
We could probably come up with a list, but it is rare that theories actually are completely wrong.

The geocentric view of the solar system has been discarded, but the Ptolemian epicycles could still be used to do astronomical calculations. In a sense it isn't even completely wrong if you take the earth as your frame of reference.

The phlogiston theory has been discarded, but we still think of heat as a sort of fluid for practical purposes.

We could probably come up with a list, but Wikipedia has already done that for us:

Apr 14, 2014
Interesting question. I think you'd need to break down 'science' into much smaller chunks (fields) to start with, and then look at 1) the complexities of the field, and 2) the current depth of knowledge.

For example, medicine alone has a large number of specialties, each with varying degrees of depth of knowledge and stats to back up its theories. Theories regarding the function of individual genes are still pretty new since we've only had the technology to really explore DNA for the last couple decades. Long term ramifications of many genetic modifications aren't proven yet, which is why people are twitchy about GMO foods. But another medical area, say heart surgery, is much more mature and has a track record that has shown tremendous declines in mortality rates. So I'd expect new theories related to heart surgery to have a higher 'success rate' than theories related to DNA modifications.

Global climate is obviously a complex field, and since meteorologists presently have difficulty accurately predicting the weather more than a few days out, it's understandable that theories are taken with a grain of salt. That said, if enough 'experts' agree that there is a significant risk of devastating climate changes, I think it's only prudent to do what we can to avoid having them proven right.
Apr 14, 2014
I've watched nutrition "science" for quite awhile, and it seems almost everything I was taught as a kid has now either proven to be incorrect or is at least now controversial. In this field, I'd say it's 90% wrong.

-Transfats were supposed to be good for you, then found to be terrible for you.
-Saturated fats were supposed to be bad for you. This is now highly controversial, and many researchers think they are good for you.
-Vegetable oils were supposed to be good for you. Now they are bad (other than olive oil). (combined with the point above - McDonald's fries were probably less bad for you when cooked in lard).
-Fish was supposed to be healthy. Still is, unless it's polluted with mercury or factory farmed, which is most fish.
-Whole grains were supposed to be healthy. Now this is controversial.
-"Low-fat" was supposed to be healthier than "whole-fat" products. This is now controversial.
+17 Rank Up Rank Down
Apr 14, 2014
The thing that changes a hypothesis into a theory is testability. It has nothing to do with the "rightness" of the idea. Theories contain the hypothesis and a method, usually mathematical, to identify testable conditions implied by the hypothesis. If a real-world test of any such condition fails, then the theory fails, and it is either discarded or modified in light of the test results and the process repeats. Some hypotheses cannot be tested empirically, because nobody has figured out how to do it. We call those hypotheses conjectures until somebody comes up with a test method.
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