When does a “theory” become a “fact”; especially when these terms are used in the Creation vs. Evolution argument?
Theories never become fact. The nature of all scientific theory is that you never know when the next experiment will suddenly require you to change (or drop altogether) the theory.
That being said there is certainly various levels of theory-hood (typically hypothesis-> theory). Laws are really just a term for a theory that is so strong that it really isn’t expect at all that it will be disproven. Scientists rarely speak in terms of moving theories to be laws. Usually you form a hypothesis and do the work to make it into a theory and if you theory is strong enough and last long enough people will just start calling it a law.
A good example being the Newtonian Laws (Theories) of Motion (at low speeds). Nobody suspects that these will ever be overturned by new findings so one can probably be safe in saying that they are fact.
Personally, I suspect that evolution would be accepted as a law if it weren’t for certain religious types. Despite claims to the contrary it is a strong theory that fits observations and made predictions of observations that have been shown to be true. But there are already plenty of threads about that in Great Debates.
OK, I’ll take a stab at it…
In science, a theory NEVER becomes a fact. Why? Because a theory is an explanation for observed phenomena. If a new phenomena is observed, then the theory must change. (Scientist/Philosopher Carl Popper called this the doctrine of falsifiability.)
Example: the phenomenon of gravity is such that objects with mass are attracted to one another. Based on observations of that phenomenon, Newton, Einstein, Hawking and others have developed explanations as to how and why it happens. If tomorrow I were to drop a pencil and find it floats in mid-air rather than fall to the ground, we would have to come up with a new explanation for how gravity works that would account for this observation.
Of course, people have been dropping pencils (and other objects) for thousands of years, and they all fall, without exception. The ones that appear to hover are not violating gravity, but are being subjected to other forces (aerodynamics, magnetism, sleight-of-hand) that counteract gravity. So, when you see something hovering, the safest bet is not to try to revise your understanding of gravity, but to first look for some other possible explanation.
There is no hard-and-fast rule as to when a phenomenon has been observed often enough and explained well enough that it receives the same “benefit of the doubt,” if you will, as gravity receives. Scientists, like lawyers, sometimes talk about “the preponderance of evidence.” And the natural sciences tend to be a fairly messy affair; careful scientists have learned to couch their language and avoid making outright statements.
With regards to evolution, the fossil and geologic records have been studies for centuries; the explanation that the Earth is very old and life has changed over the course of time has been around for at least a couple hundred years; Darwin’s explanation of natural selection (descent with modification) was published some 140 years ago; Mendel’s explanation of inheritance through genes is about 100 years old – and in all that time, all the observed evidence has fit the expected patterns. No one has ever knocked a hole it in. As with any science, the details are in a constant state of revision, but every serious scientist (and there’s a loaded phrase) is convinced that evolution, at least in its broad strokes, is the correct explanation for life’s history. All contrary evidence is the equivalent of a floating pencil – unsettling perhaps at first glance, but fairly easy to explain upon closer investigation.
A theory does not become a fact. A fact is a verifiable datum, observed, and reproducible under controlled conditions. A theory is a hypothesis which has been advanced as an explanation for a group of facts, and subsequently tested by observation of other facts, and determination of whether its predicates (those other things which should be facts if the hypothesis is true.) are true.
When that is done, the hypothesis is presented to a number of other investigators as a theory. Those investigators will then try to find facts that support, or refute the theory. A group of theories that are mutually supporting and not contradictory provide a model for what we believe to be true. When new evidence (new facts) are found which seem at odds with theory, the scientific method requires that the facts be examined, and the theories examined as well. New hypotheses may be developed, and at times an entirely new model will need to be developed.
Some theories are well established, and very well supported by numerous examinations of facts under very well controlled situations. When a report is made that a new fact shows all the theories under that model are wrong it may be true that the model must be changed. It is also possible that the “fact” presented is incorrect. Examination by multiple investigators under strictly controlled circumstances would be required to overthrow decades of prior research. It does happen. The entire model of physics is in some considerable state of change, in the last few decades. That does not mean that Einstein’s General Theory of Relativity is now shown not to be a fact. It never was a fact; it was a hypothesis that proved very useful in explaining much about the facts then observed. New facts have been observed, and the theory is now seen as incomplete.
Neither facts nor theories should be mistaken for claims and reports. Claims and reports are matters of journalism, or literature, not science. Entertaining, at times, and even profound in their own way, but not the same sort of thing as a fact, or theory in the view of the scientific method.
Faith is never an element of theory, in science. That does not mean that it cannot be an element of human endeavor, only that it is not a part of the scientific method.
Actually, I should make it clear that a theory may never be called a law even if it is very strong. There is no process or criteria that cause a theory to become a law. A law is simply a term commonly used for very tight & strong theories.
I could make a theory called “Glitch’s Law of AI Interaction”. Any scientist viewing it would know that I mean theory, and although they might be a little miffed at my arrogance for calling it a law it really wouldn’t mean anything more.
Now, other scientists may call it “Glitch’s Theory” or “Glitch’s Law” and one term or the other may catch on. Whichever one catches on is the one it will be called. Decades later (or centuries) if the theory is still considered solid and was called a theory still people might start calling it a law and the new name might stick. I.e. it is just a term used commonly in this case for emphasis that this is no ordinary theory.
I hope that makes the law/theory thing clearer, I didn’t think my original post did.
Over in Great Debates, in the “The Earth is flat, I read it in the paper. . .” thread, on pages 2 and 3, David B and Phaedrus each posted several definitions for “theory”:
David on 10/23 8:36 a.m. http://www.straightdope.com/ubb/Forum7/HTML/000488-2.html
Phaedrus on 10/25 11:27 p.m. http://www.straightdope.com/ubb/Forum7/HTML/000488-3.html
The discussion is a bit rancorous, but it does bring out various views of the term “theory.”
Glitch, ya’ beat me to the draw!
As for “Laws,” I seem to recall Steven Jay Gould writing that “Law” and “Theory” are, in fact, equivalent – it’s just that somewhere in the 19th Century scientists began to realize that new observations could overturn existing explanations (then known as “laws”); and that more than one plausible “law” could be offered for many then-newly-discovered phenomena. So, as a way of hedging their bets (and to avoid looking foolish, having to retract previously promulgated “laws”), they switched to the less absolute, more accurate “Theory.”
Today, “Theory” has connotations of “educated guess,” which Creationists use to cast unwarranted doubt on the well-documented phenomenon of evolution. For that reason, I prefer to use the word “explanation” when possible.
My thanks to Glitch, Beruang, and Triskadecamus for their replies. I have always considered a theory to be a proposed explanation of an event or events that are regarded as conjectural in contrast to well-established phenomena. As a “hypothetical” example, let’s say that several hundred years ago I come up with the proposition (theory)that, contrary to popular belief, the earth revolves around the sun. Years later, it is shown that this actually does occur. My “theory” now becomes a “fact”, does it not? I am deliberately leaving out the term “law” from this discussion.
While I agree, in essence, with y’all, I think we, in trying to distinguish between these two nouns, are getting caught up in semantics.
In terms of everyday speech you are absolutely correct. However, it is only a fact that at this time the Earth revolves around the Sun. The Heliocentric Theory could someday be false, inaccurate or incomplete (just like Newton’s Laws are considered incomplete and not wrong). Maybe if the magentic interflux resonance (is that Star Treky enough for ya ;P) of the Sun and Earth will somebody cause a massive chain reaction that will bring the Earth to a screeching halt and the Sun will start orbiting us! So like all theories it fits observation (the Earth does revolve around the Sun) and make predictions of future observations (the Earth will continue to revolve around the Sun). If the future observations do not coincide with the theory the theory would need to be adjusted.
I meant to bold everyday speech because it is an important part of the above post.
If somebody said to you “The Earth revolves around the Sun”, to which you replied “That is only a theory!” You would be right scientifically (we don’t know for sure that the Earth will always revolve around the Sun), but they would rightfully so consider you a goofball. (N.B.: If they said “The Earth revolved around the Sun yesterday” and you replied “That is only a theory!” you would be wrong. Since the magnetic interflux resonance did not happen yesterday the Earth did in fact revolve around the Sun, there is nothing theoretical about it).
It is still a theory that the Earth and Sun revolve about their common center of gravity. However the number of observations (the facts upon which the theory rests) is very large, and the number of outcomes which the laws (by which I mean the very specific mathematical relationship of the observations) of motion have precisely predicted is . . . well, astronomical.
The facts are that the sun appears to move in a complex path across the sky, varying from day to day over a repeating cycle. That is what you can observe. If you use instruments of sufficient quality, you can describe that path with extreme precision. You can move to different locations, and determine that that path is not precisely the same for different points of observation on the Earth. You can record and compare the observations of many observers over a long period of time and find out that the path changes in several different ways over different periods of time.
Using all these facts and the equally large collections of facts about others objects seen in the sky, collected by other observers, and a very tedious process of mathematical manipulation, you can develop the same theory that Kepler and Newton did, using the data compiled by Tycho Brahe, and others. The facts are that there are specific patterns in the position in the sky which are consistent with the theory that the objects orbit about the center of their masses, and the mass of the Sun is several orders of magnitude greater than the lesser objects. The mathematics that describes this would then be hailed, or reviled, according to the beliefs of those who hear your theory.
When you have done that, another smart person will go out and find that extremely massive, or very rapidly moving objects do not follow the predicted patterns of your Laws of motion. That will not make you happy, if you are still alive, however it will not cause the Sun to start circling the Earth, either. You theory describes the Earth and Sun just as well as it ever did.
Wow. I think I’ll just sit back and take a week or so off.
ahale1929, don’t you have a dictionary?
You are confusing “theory” with “hypothesis”. A hypothesis is a possible truth that is capable of being disproven with empirical fact: “Copper won’t rust underwater”.
Theory is different; theory is the art of explaining things in such a way that they make sense. Theory is usually much larger in scope than a hypothesis, and often large parts of it cannot be disproven: “Material hegemony is the root of political power”.
What may not be obvious to you at first is that facts, by themselves, don’t explain things; in fact, the more facts you have, the greater your need for theory to make sense of it all! If you took all the individual measurements of positions of planets in the sky over the last 1000 years, expressed in right ascension and declination to 1/10 of a second of arc, and gave that data to a 1st century person of good education along with a clear explanation of how RA and dec are mapped in the sky, this person most likely would look at the data and know immediately that the planets orbit the sun. To see the pattern in the data is to **theorize **, and it is akin to staring at a table full of disconneced puzzle pieces and suddenly intuiting what the picture on the puzzle box cover looks like. (It’s a really cool feeling, too!).
Theories tend to generate hypotheses, which **can ** be tested; the validated hypothesis does not ** prove ** the theory, but it sure gives you a good signal that you do indeed grasp the general picture if most of your testable hypotheses are validated.
Designated Optional Signature at Bottom of Post
Impressive bunch, aren’t they, Dr. Fi?!
If tomorrow I were to drop a pencil and find it floats in mid-air rather than fall to the ground, we would have to come up with a new explanation for how gravity works that would account for this observation.
So when it falls only into my lap I invent the Theory of Levity?
My dictionary says Mendel died in 1884, so wouldn’t you figure his theory was some 125-150 yr old, even though it might’ve lain undiscovered until some 100 yr ago?
You say a theory may never be called a law and then, two sentences ahead, you say theories are commonly called laws. I think you need a new hypothesis. . .like, whatever I say may be contradicted two sentences ahead. Now, Murphy’s laws don’t have any Glitches in them.
If you claimed the Earth revolved about the Sun 200 yr ago, and I said, “That is only a theory,” wouldn’t I be right? Because, in claiming that was so, you had to believe what others before you recorded. Those other guys could’ve lied.
If you have to worry about them having to revolve about their common center of gravity, rather than the Earth’s revolving about the Sun, don’t you have to worry about the effects of the other planets and Solar System junk’s effects also, since they contribute much more mass than the Earth does. But you can pick any frame of reference you want, can’t you?
Ray (DISCLAIMER: All statements made here are only hypotheses and their author is not liable for any accidents between any heavenly bodies or any less heavenly ones. And this is according to law, not theory. And if the author be proved wrong, his hypotheses still stand or revolve or something. )
Many thanks to all of you for your erudite, if not somewhat verbose, attempts to set me straight. It is now obvious to me that the word “fact” really doesn’t exist and should be stricken from our lexicon.