I sure wish more people understood the meaning of theory in science, but at least Piers Sellers does a good job of explaining the concept. I try to hammer into my students (as my teachers hammered into me) the primacy of evidence — observation and measurement — but evidence always has to be for or against something, and that something is theory. You can’t have a theory without evidence, and you can’t have evidence without a theory to give it meaning. So I’m always happy to see another explanation of this core concept of science.
Fundamentally, a theory in science is not just a whim or an opinion; it is a logical construct of how we think something works, generally agreed upon by scientists and always in agreement with the available observations. A good example is Isaac Newton’s theory of gravitation, which says that every physical object in the universe exerts a gravity force field around itself, with the strength of that field depending on its mass. The theory—one simple equation—does a superb job of explaining our observations of how planets orbit around the sun, and was more than good enough to make the calculations we needed to send spacecraft to the moon and elsewhere. Einstein improved on Newton’s theory when it comes to large-scale astronomical phenomena, but, for everyday engineering use, Newton’s physics works perfectly well, even though it is more than three hundred years old.
One danger of the public misunderstanding of this idea is that they do equate theory and opinion; they tear down successful theories with rhetoric and ignorance, and they also elevate nonsense by labeling it, without comprehension, a theory. And I could piss in the snow and call it a book, too.
But theories are abstract, after all, so it’s easy for people to get tricked into thinking that because something is based on theory, it could very likely be wrong or is debatable in the same way that a social issue is debatable. This is incorrect. Almost all the accepted theories that we use in the physical and biological sciences are not open to different interpretations depending on someone’s opinion, internal beliefs, gut feelings, or lobbying. In the science world, two and two make four. To change or modify a theory, as Einstein’s theories modified Newton’s, takes tremendous effort and a huge weight of experimental evidence.
This is something that should be explained to everyone visiting Answers in Genesis and their horrible dishonest “museum” and “ark park”. The central argument Ken Ham always makes is a demolition of the whole concept of theory — he claims that any alternative explanation, no matter how much it ignores the evidence, is a theory, and all theories are equal, and therefore, his bizarre, highly subjective and ideologically driven interpretation of the words of his holy book are just as much deserving of the title of “theory” as the hard-earned, constantly tested, well-supported by evidence theory of evolution.
And that’s dangerous. Ken Ham uses the degradation of theory to peddle nonsense to the rubes and make money and promote his narrow religion, but as the article explains, it’s also being used to corrupt decision-making about climate that endangers every human being on the planet.
Maybe science should just get a new word, since “theory” is apparently so tainted.
Maybe cretinists should get a clew since their “understanding” is apparently non-existent.
PZ, you are aware you can piss in the snow and call it art? Check out “Piss Flowers” by Helen Chadwick
“Particle Fever” was a very good movie but I cringed when physicists used the word theory instead of hypothesis.
Tell the rubes that the structures of all modern* highway & railroad bridges, & all structures for modern* buildings, etc., were designed according to the theory of structures.
That should put the fear of god into them. Oh no, the rubes already have that.
* where modern means since the beginning of the 20th C,
To me this is right up there with people in movies panicking when the reactor goes critical.
‘They tear down successful theories with rhetoric and ignorance’. Obviously they merely attempt to tear down successful theories, only displaying their own ignorance while doing so.
There will always be truly ignorant people who believe themselves wiser than others, but the phenomenon of such idiots being taken seriously seems to be only truly widespread in the US and the Muslim world. The rest of us will carry on using ‘theory’.
This is all to true. But theory comes in softer and harder forms as well. Some we have great “faith” (proper use i hope) in, and others we are not so sure about. Also philosophers still use the word theory for what in my view should be called “accounts” or possibly “frame works” of thought which adds to the confusion.
Really, PatrickOslund? Please give an example of these harder and softer forms of theory, because I don’t know WTF you’re talking about.
The word “theory” has multiple definitions, which is problematic and allows people like creationists to swap out definitions to cause confusion. There needs to be clarity when talking about a “scientific theory”, which is markedly different from the layman’s definition of “theory”. I’ve found when you challenge someone to tell you what the (for example) “Scientific theory of intelligent design” is you’ll find they actually have nothing to respond with.
Artor @9: Soft: String theory. Hard: Electroweak theory. Does that help?
parrothead@10, I tend to doubt saying (e.g.) the “Scientific Theory of Evolution” will neither cause the cretinists any problems / pause nor provide them with any insight, as they seem to hear “Scientists’s Guess is Evolution” and fabricate nonsense from that imagined starting-point…
I concur better clarity is useful, but dropping in an extra word does not provide that clarity (at least for cretinists and other woo-woos), albeit it does help to reinforce a presumably-accompanying lesson / description / discussion about just what is meant by “(scientific) theory” et al.
Rob Grigjanis @11:
Thanks. Good examples.
Artor @9:
You wont get a rise out of me.
It’s the same problem as when we talk about privilege. “I don’t have a yacht!” It’s amazing how hard people cling to one meaning of a word if it means they get to disagree with reality.
Well, it might be about to say something really scathing to them!
@ 1. jonmelbourne
We talk about Newton’s Laws of Motion even thought gravity is a theory as the bumper sticker says—we simply need to talk about the Laws of Climate Change.
That will teach those deniers! Well teaching them may be difficult but it might confuse them even more.
Regardless of scientific evidence, a theory can only be a theory if it does not contradict Bible facts – otherwise it’s just a worldview and (in the case of the theory of evolution) an anti-god religion. Apparently.
As an etymologically-minded sod, it has always bemused me that the word “theory” does not, sfaic find out, have anything to do with the amazingly similar word “theos” (god).
Online Etymological Dictionary (links & bolding omitted):
Unless (no such clues in the reference above, or anywhere else I’ve looked) maybe the Greeks originally described their gods as “watchers” – and humans as their entertainment. Pretty lowbrow bunch, Zeus et alia…
The creationists argue that disproving a theory also disproves the facts. I confronted one creationist with the idea that when a police officer finds a dead elderly man with a bent neck at the foot of a staircase, she would likely theorize that the man died when he fell down the stairs and broke his neck. When they moved the body they discover a bullet hole in his chest. Thus the theory is wrong, but the man is still dead. Disproving the theory of evolution doesn’t disprove the fact of evolution.
One problem is addressed by the OED specifying that dictionary is Desriptive, not Prescriptive. Meaning the dictionary just describes how words are used, does not predefine their meaning, establishing rules of usage, etc.
While this could be used as a counterargument to the OP, that to fixate on a single meaning of a word that could be used as an oxymoron, just relating observation.
Too often “laymen” get fixated on the casual use of “theory” as synonym for “guess”; unaware of the more rigorous definition used by Science. Films of mystery stories are usually accompanied by the detective spouting “I. have. a. theory.” When they really mean ‘a thought out guess’ about the identity of the guilty party.
*blink*
Theory, the rigorous one, is also technically a guess, that can be tested on all specific implications and provides questions that can directly disprove it. (aka Falsifiability ). Good luck getting that out of AIG “theory”. All of AIG’s guesses, have been treated like Theory and collapse instantly with the first most obvious question.
*blink*
the thing about dictionary was meant to be an argument against dropping the word because it’s “tainted”. Words have many meaning, some have definitions that are mutually exclusive. So when theory is used inappropriately (“oh tha’ts just a theory”) It’s useful to remind them that words can have more than one meaning and state which one is being used.
*shrug*
How about spell different? Theorie vs theory
but then defining which spelling for which defn would be argued perpetually. so nope.
how about capitalization to signify the rigorous defn vs lower case for casual?
–
ugh
all just a theory, hmm
Piers Sellers is pretty great. I had the pleasure of hearing him talk about his amazing career yesterday. He and his teams (with a few years off to be an astronaut, as one does) figured out how to scale up the interaction of plants with CO2 and water from “a bowl of spinach” to satellite measurements of the entire world. It’s a wonderful story, and he is a fantastic speaker. If you get a chance to hear him speak (and you won’t have many such chances), I recommend it.
He was interviewed by the Forecast podcast not long ago, so if you want to geek out for an hour, check it out.
“Theory” is one term whose misuse by non-scientists, especially by Creationists, is very annoying. But there’s another term which is even worse: “the scientific method”. There is no such thing as the scientific method. Every scientific field, and every sub-specialty within a field, has a different scientific method. Different standard experimental techniques, different criteria for confirming or rejecting hypotheses, different requirements of experimental reproducibility and controls, different levels of reliance on numerical/quantitative analysis vs. qualitative observation and description, different modes of debate, different objectives. The “scientific method” is supposed to be about how theories become hypotheses, and then laws, right? But many scientists don’t think about hypotheses, theories, or laws at all; they spend their energy trying to accomplish practical goals: coming up with a recipe to make a new molecule, or a way to get a biological compound to form a large single crystal whose structure can be analyzed by x-ray diffraction, or a technique for measuring a higher-resolution spectrum, or a way to make a stronger magnet, a brighter laser, or an emptier vacuum. The so-called “scientific method” is really a philosophical method and actual scientists almost never think about it.
No. Laws are numerical calculations, like the Ideal Gas Law.
Hypotheses have a modicum of evidence to back them up, and are the starting points. Full theories, like the Theory of Evolution, have a large amount of evidence to back them up. Laws are merely a small piece of a theory, and the Ideal Gas Law is a section of the Kinetic Theory of Gasses.
Nerd:
RE: “Laws are numerical calculations, like the Ideal Gas Law.” No, not necessarily numerical calculations. Isn’t the Pauli Exclusion Principle a law? Most of us would certainly say it is. But it’s not a numerical calculation; the only number in it is one (only ONE fermion can occupy a particular quantum state), and there’s no calculation involved.
Nerd: RE: “Hypotheses have a modicum of evidence to back them up” No, a hypothesis is just a possible proposition, does not require any evidence and carries no implication of any connection to an actual thing or fact. Hence the term “hypothetical”.
Nope, hypothetical or supposition would be used. Any attempt to do a hypothesis that doesn’t include a piece of evidence or two is simply wishful thinking. Which is why I said a modicum of evidence. It doesn’t have to be much.
You are quibbling terms you appear to know nothing about. Philosopher perchance?
For making QM calculations. Mathematical.
From Miriam-Webster: HYPOTHESIS
1a : an assumption or concession made for the sake of argument b : an interpretation of a practical situation or condition taken as the ground for action
2: a tentative assumption made in order to draw out and test its logical or empirical consequences
No “evidence”, except perhaps by implication in 1b.
And you don’t use the Pauli Exclusion Principle to make QM “calculations”. You use it to determine occupancy of QMical states, AFTER calculating the states. A purely qualitative principle, (quantitative only in that ONE is a quantity).
RE: “You are quibbling terms you appear to know nothing about. Philosopher perchance?” Well I was a philosophy major in college, but I am a retired immunochemist, and my graduate work was in physical chemistry.
handsomemrtoad @28:
I beg to differ. It’s used, for example, in calculating exchange interaction effects, and the Chandrasekhar limit.
handsomemrtoad:
Indeed, some could have many different scientific methods, not just “a” method for that sub-field or “the” method for all of science. I mean, in some sense, you do two different experiments and you have two different methodologies. They might have a whole lot in common (enough to say it’s the same) or they might not. In any case, you can try lots of different approaches to a problem, and maybe several of them will work just fine.
No, I don’t think I’d say anything like that. Why would laws be at the end of a chain like this? A law describes some regular features of nature — perhaps an especially informative or useful sort of fact about what nature consistently does; but nevertheless just another contingent fact, like the fact that I wrote this comment. The law should represent things in a way which humans can understand, and if it’s true it should be consistent with everything else we know (if not, then we’ve got problems). I wouldn’t characterize it as a “numerical calculation,” but math is obviously an extremely useful tool for representing the facts consistently/unambiguously, in a way (some) people can understand and use.
Anyway, you can have a theory which aims to give you some understanding of that stuff. It might incorporate lots of different laws and hypotheses and postulates and so on, as it’s telling you this story or painting this picture. So, the end result of all of this work doesn’t seem like it would be a candidate for a natural law itself. A theory relates/explains factual items (including laws but any facts may do), putting them together in a way so you can try to comprehend what the facts say about the world. Then maybe you use all of that to make interesting predictions/inferences, design technologies, find deficiencies and provoke new research, etc.
Well, that may be true of some scientists. If you’re happy to say “it works and I’ve done my job, give me more grant money,” that’s fine I guess. I still want to understand the world; that is, given that these practical or technical things work the way they do, what can we say is true of the world to explain how/why they work? It’s a philosophical issue as well, but it’s a scientific one as long as a goal of science or scientific theories (not this or that scientist in their work environment) is to help us understand the world. If you’re just going to build things or run experiments without worrying about what any of it means, you’re some kind of an engineer or technician. That’s a fine job to have, but science (as I understand it) is aiming for something else.
that sequence seems exactly inverted. As in
(1st): Laws are observations of how magnitude of one quantity results in a particular magnitude in a different quantity.
a set of of laws can then be explained together by proposing a theory of the interrelationship. Initially the proposed theory is presented as a hypothesis (2nd) until much examination and experimentation accepts the hypothesis as a Theory (3rd).
An error often seen is the WAG that a Theory ain’t good enough yet to become a LAW. Theories explain laws, they don’t not become laws. Laws are components of theories not the result of theories.
yes IMO
And it’s the loneliest quantity you’ll ever know.
Some interesting comments under this:
http://www.charismanews.com/culture/59326-ken-ham-identifies-new-religion-of-death
Physics has laws. Math has laws. Science has theories, and all theories were once a working hypothesis. I think a lot of people learn about theorems and hypothesis in geometry, and then think the terms have identical meanings for a scientist.
Tell that to the hundreds of general chemistry students I taught back when I was an academic, where the Pauli Exclusion principal was used to show only two electrons (leptons) per energy level on an atom, compared to the bosons, where the Pauli exclusion principal doesn’t apply.
The Exclusion Principal explains why there are 2S outer electons, 6P outer electrons, 10D outer electron, and 14F outer electrons.
and if we get to G orbitals, 18 outer electrons. I believe that is called the periodic table….
Nerd @35: That doesn’t refute handsomemrtoad, since they mention occupancy as a use of the PEP. What does refute is the energy levels of states which have (say) two electrons with parallel versus anti-parallel spins.