What is "scientific theory"?

[Lefty]

Yes, I'm in a sense taking an unscientific poke at science. The term "scientific theory" has always troubled me with the way it is used in science. As a layman, it seems to me to fall short of the intent merely by using the word "theory".

 

The reason I bring this up is I have run into this topic in another thread here in these forums. Years ago I was "schooled" by men of science when I questioned why evolution is called "The Theory of Evolution". I asked why is the word theory used if evolution is fact. BOY was that a...lively discussion!

 

I have read many answers to this question, and I still come away with the impression that the word theory is lacking somehow. This is NOT a thread about evolution so please let's not cover that here. This is about the thread title. I just use evolution because it uses the word theory so commonly all the while the majority of the public likely has no clue how science uses the word theory.

 

Among scientists, the use of the word is understood. To the unlearned, the word "theory" I suspect is most commonly thought of as something that is not proven fact.

 

 

Quote

 

https://simple.wikipedia.org/wiki/Theory

A theory that can produce a statement that is not true, a theory that can predict something that does not in fact happen, or that predicts that something will happen but it does not happen, is not a correct theory. This idea has a big hole to fall into. Scientists can look at experiment after experiment, and they may always find that what theory says is true. Years may pass, and then somebody looks at one more experiment. That experiment shows that the theory is false, and every time they do that experiment it shows that the first time was not some kind of accident. The philosopher Karl Popper gave the example of people in Europe before 1492 who wanted to give scientific descriptions of birds. One bird they worked on was the swan. Somebody proposed the idea, "All swans are white." All of the swans that were checked in their century were white. When Europeans first sailed to Australia, the first swan that they saw was black. Suddenly the old scientific description of swans had to be changed.

So it is never possible to prove conclusively that some theory is correct. A "black swan" may come with the next experiment. It is possible to prove some theories are incorrect. Science makes progress by using one theory until it fails, trying to understand why that theory failed, and then making a better theory. Some theories are very well confirmed, that means that they have been tried over and over again and have never yet failed. When a theory is well confirmed people trust its predictions.

It is possible to prove conclusively that some theory is incorrect. Proving a theory is incorrect makes it possible to find a better theory and thus to make progress.

 

1

 

From the above explanation, it seems the use of "theory" means this is what we believe to be true until it is proven incorrect.

 

"...When a theory is well confirmed people trust its predictions...". That statement sums up my point. Can "well confirmed" [sic] be considered "fact"? Also using the word "trust" is a little unsettling seeing I don't trust humans as I do know they make mistakes and can have a bias. For science to tell me "trust us we know what we are doing!", all the while tending to do an awful lot of educated guessing and present it to suggest it is proven fact just doesn't sit well with me.

 

Evolution or "The Big Bang Theory" as an example, it is called theory because it has not been proven false? Can one say they are scientific fact?

[♦ Fuego ♦]

Here is a blurb from a community college about what a theory is ("After much study, the evidence shows _____. The rest of you scientists check the methodology and results.") versus a hypothesis ("maybe it's like this ____. Let's see if the evidence supports it.")

 

https://www.oakton.edu/user/4/billtong/eas100/scientificmethod.htm

 

In short, a scientific theory is an idea about how something happens based on observable and repeatable evidence that has faced intense scrutiny by other qualified scientists and seems to be a valid explanation. That is far different than where it starts out, and completely different than "It must be this way because ____ and I will find the evidence that supports this and ignore the rest". 

[wellnamed]

The point in the wiki entry about black swans is just a point about logical induction in general, and also of abduction (inference to the best explanation). Inductive conclusions do not have the same logical force of necessity that deductive proofs (e.g. in math). This is an inescapable fact of epistemology that one just has to accept. Theories are not facts in some simple sense.

 

But, it may be helpful to think in terms of probability. The better tested a theory is, that is the more opportunities there have been for empirical falsification, and the wider the range of phenomena for which the theory has been tested, the more likely it is to be correct, or to put it another way: the space of possible phenomena under which the theory might fail is smaller. Think of Newtonian mechanics here: that theory still works, we use it all the time. The theory was not "wrong" within the domain it was originally supposed to explain, it just turned out that it was inadequate to cover the entirety of physical phenomena. It fails at relativistic speeds and when dealing with sub-atomic behavior. With relativistic mechanics, the theory was mostly just expanded so that the scope in which it failed became even smaller.

 

So, the problem with saying "oh, that's just a theory" (in the sense of not having complete certainty) is that this way of thinking collapses knowledge into a false choice where we either know something with certainty or not at all. But in truth there's a wide range of certainties. I am very confident in the correctness of the theory of gravitation, especially within the limits of the applications I might use it for. But it might turn out to be incomplete with respect of black holes, say. Yet saying "it's only a theory" pretty dramatically understates the reasonable level of certainty we can have, given the empirical support for the theory. Other scientific theories may be less certain, but still the best explanations we currently have.

 

It's probably also worth keeping in mind that for some theories we judge them on usefulness. That's why we still use newtonian mechanics. It's not "correct" in some sense, but if you want to write a computer simulation of a billiards table it is highly useful. There are degrees of "correctness", if you will. Mathematically there is the concept of error, especially in statistics. If the error is small enough to not matter for your use case, then why worry about it?

[wellnamed]

Another thing I like to think about, regarding knowledge in general:

 

One of the classical definitions of knowledge is "justified, true belief". That is, we can say we "know that P" if and only if we believe that P, we are justified to believe that P, and P is true. There are some interesting issues with that definition (cf. Gettier problems), but I think that really all of epistemology boils down to just that one element: justification.

 

Putting aside technical terminology for a second, what makes science valuable as an approach to knowledge is just the effort to justify beliefs in a more rigorous way. That's what all the talk about falsifiability, or observability, repeatability, and the qualifications of scientists (as fuego mentioned) is for. That is the essence of "scientific method". So if we call one idea "scientific" and doubt that another is equally scientific, then what we're really doing is evaluating epistemic justification, and I think it's more accurate to put it that way than to say we're evaluating some level of certainty. The other reason this framing is useful is because it tells you how to evaluate ideas: look at the how the idea can be arrived at -- the methods used to collect, analyze, and make generalizations from data (observations). This is why a theory which may be rather uncertain can still be scientific, if the theory is formulated following scientific methods. This makes sense because science is not just the body of accumulated knowledge about the world, but also the accumulated body of knowledge about the epistemic reliability of various methods for gaining knowledge in general.

[pantheory]

This is a good posting for this topic since the word theory in science has no exact consensus definition. The meaning of "scientific theory" generally means a coherent group of propositions and hypothesis formulated together to explain scientific observations, contains a broad group of facts or phenomena in the natural world that has repeatedly been tested for confirmation through experiment and/or observation; such theories incorporate facts, laws, inferences, and tested hypotheses; scientific theories must also be both testable and falsifiable.

The theory of Evolution, for instance, is based upon Darwin's theory of natural selection. It contains the intuitively obvious cliche "the survival of the fittest." Those individuals that adapt well to their environment, live longer. Those that more easily and readily proliferate will have more offspring. Together a population will be dominated by better adapted and more prolific genetics. The theory of evolution also contains a very large amount of hypothesis that are less substantiated, some of which will change over time. The over-all theory is substantiated by a mountain of evidence, most of which cannot be disputed.

Of course there are other factors involved in evolution such as epigenetics, gene folding factors etc. that play a part in both micro and macro evolution, that are not a part of the theory of Evolution via natural selection.

Those still believing in God's creationism are rarely ever knowledgeable concerning the mountain of facts, experiments, fossil records etc. involved. Evidence can also be misinterpreted and rightfully disputed, but not a mountain of evidence. A mountain of evidence is more than theory, most of it is fact.

 

 

 

[Lefty]

Thank you for the replies.

 

That's some interesting comments, but as I said, I already have heard the story pretty much presented as it has been here. However...

 

...the only part that comes close to actually answering is this by wellnamed, "...Theories are not facts in some simple sense...."

 

I knew from the start that there would be paragraphs written but would likely not answer directly the question.

 

8 hours ago, Lefty said:

Evolution or "The Big Bang Theory" as an example, it is called theory because it has not been proven false? Can one say they are scientific fact?

 

Dare I ask, can a simple yes or no suffice? A brief explanation of why yes or no is fine. Remember, I'm not asking for a scientific paper here, just asking a rather basic question that the average person can make sense of.

[wellnamed]

The reason for the paragraphs is to point out that you're probably asking the wrong question to begin with

 

18 minutes ago, Lefty said:

it is called theory because it has not been proven false?

 

Like I said, the labeling has more to do with the use of scientific methods than anything else. It would still be called a theory if it were proven false. It would just no longer be used in the same way. For example, you could refer to the idea of the "aether" as a scientific theory, it's just one that's been disproven.

[Lefty]

1 hour ago, wellnamed said:

The reason for the paragraphs is to point out that you're probably asking the wrong question to begin with

 

LOL, touche'

[disillusioned]

13 hours ago, Lefty said:

 

From the above explanation, it seems the use of "theory" means this is what we believe to be true until it is proven incorrect.

 

"...When a theory is well confirmed people trust its predictions...". That statement sums up my point. Can "well confirmed" [sic] be considered "fact"? Also using the word "trust" is a little unsettling seeing I don't trust humans as I do know they make mistakes and can have a bias. For science to tell me "trust us we know what we are doing!", all the while tending to do an awful lot of educated guessing and present it to suggest it is proven fact just doesn't sit well with me.

 

Evolution or "The Big Bang Theory" as an example, it is called theory because it has not been proven false? Can one say they are scientific fact?

 

The definition of a scientific theory varies somewhat by discipline, but there are definite commonalities. The essence, I think, is that a scientific theory must meet three criteria: it must be descriptive, predictive, and falsifiable. That is to say, a scientific theory must accurately describe our observations about some aspect of the universe, it must make definite predictions about what we should observe under certain conditions, and it must able to be shown to be false, at least in principle. Usually, the falsifiability follows from the predictions; if the predictions turn out to be false, then the theory must either be amended or rejected.

 

Another way of putting this is that a scientific theory is a model of some aspect of the universe. We use these models as long as they work. When they don't work, they need to be replaced or updated. So it is true that scientific theories are never 100% proven fact. I would argue that 100% fact is not actually the business of science.  Science doesn't prove anything. To explain what I mean by this, I'd like to consider an example of an actual scientific theory.

 

Let's look at Newtonian mechanics. This is a really good, really well-established scientific theory. So much so, that it's tenets are called "Laws". The Laws of motion. The Law of gravitation. The Law of conservation of momentum. And so on. The fact that these principles are called "Laws" can give the illusion of absolute certainty. It may even tempt us to think that the theory is no longer held to be falsifiable. Not so! The theory definitely is falsifiable, it's just that we have billions of pieces of experimental data, and they all agree with the theory. So it seems pretty damn accurate. Now, of course, it does break down under certain conditions (see: relativity, quantum mechanics, etcetera), but on a macroscopic scale, under "normal" conditions, it just works. And it's a good thing it does: it lets us build planes, trains, and automobiles. It let us go to the moon. It definitely isn't perfect, but it's pretty damn good.

 

Now, some people would be inclined to say that Newton's laws of motion, for example, are facts. I would be inclined to agree with this, subject to the qualification that they are scientific facts. Scientific facts are never 100% certain. 99.9999%, maybe. But not 100%. Now I am tempted to ask what facts are, what knowledge is, what truth is, and so on. We can go down these roads if you want, but I'm going to leave this aside for the moment. If you want to pursue it later, I'm game.

 

By now I hope it's clear that it's true that a scientific theory is never 100% sure, but it isn't exactly "what we believe until we are proven incorrect". In the strictest, literal sense of the words, that's what it is. But the phrasing gives the wrong impression. There comes a point when there is so much evidence that we don't really question a scientific theory. Nobody bothers to question Newtonian mechanics anymore for this reason. We know that it works, and under what conditions it works. It just works. In general, though, I think there is an important underlying point here. I've written before on these boards that I think it is incorrect to speak of Laws of the Universe. My feeling is that is the Universe, and there are our models of the Universe (read: scientific theories). And it is our models that have Laws. Some models are better than others, and when a model is very good, we grow tempted to refer to its Laws as the Universe's Laws. But this is incorrect, in my view. I agree with Haldane, that the universe is probably "not only queerer than we suppose, but queerer than we can suppose". And I also agree with Bohr (who, for my money, may well be the greatest physicist ever to have lived) who, speaking of the implications of quantum mechanics, said "There is no quantum world. There is only an abstract quantum physical description. It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we say about Nature."

 

That final quote is particularly pertinent, I think. Physics, and science in general, is not so much about what Nature is like as it is about our attempts to describe and understand Nature. We may not actually be equipped to do this properly. But science is our best attempt. And scientific theories are the models we build when we try to do science.

 

And, the good ones seem to work. So there's that.

[pantheory]

On 4/4/2019 at 11:20 AM, wellnamed said:

The reason for the paragraphs is to point out that you're probably asking the wrong question to begin with

 

 

Like I said, the labeling has more to do with the use of scientific methods than anything else. It would still be called a theory if it were proven false. It would just no longer be used in the same way. For example, you could refer to the idea of the "aether" as a scientific theory, it's just one that's been disproven.

 

Many think the theory of aether has been disproved but in fact it was not, and there are many modern aether theories and a number of scientists that believe in aether today. The word aether is no longer popular so scientists have come up with different names for it such as the zero-point-field, space-time fabric, quanta-sized space, dark matter, quantum foam, etc.

 

https://en.wikipedia.org/wiki/Aether_theories

https://arxiv.org/ftp/physics/papers/0604/0604207.pdf

Modern aether theories are compatible with modern physics and published in peer-reviewed journals:

I. Schmelzer, A Generalization of the Lorentz Ether to Gravity with General-Relativistic Limit, Advances in Applied Clifford Algebras 22, 1 (2012), p. 203-242, resp. arxiv:gr-qc/0205035.

I. Schmelzer, A Condensed Matter Interpretation of SM Fermions and Gauge Fields, Foundations of Physics, vol. 39, nr. 1, p. 73 (2009), resp. arxiv:0908.0591

For the most part these theories are ignored but such theories can explain many aspects of physics that are otherwise much more difficult to explain.

 

[wellnamed]

Fair enough, for my purposes the fact that it's not widely accepted is good enough for answering the question. The original concept of the aether is wrong, at the very least, I think. New theories adopting that term notwithstanding?

[pantheory]

On 4/5/2019 at 6:22 PM, wellnamed said:

Fair enough, for my purposes the fact that it's not widely accepted is good enough for answering the question. The original concept of the aether is wrong, at the very least, I think. New theories adopting that term notwithstanding?

 

The original concept of the aether had at least one primary assertion. The aether was supposed to be the carrier of light, EM radiation, called the luminiferous aether, the "ocean" where light waves were assertedly created and traveled within. Others, including Newton, proposed aether as also being the pushing source of gravity, Optics 1717, second edition. There are still many theorists including myself that still believe and theorize an aether of some sort. So for us no aspect of the existence of aether has ever been disproved.

 

Yes, such theorists are certainly a minority, never-the-less as you can see in the link below there continues to be a great number of these credentialed theorists still following and proposing new aether theories on an ongoing basis.

 

http://sciliterature.50webs.com/RelativityDebates.htm