# Can anything be proved in science? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [October 14, 2017, 3:22pm UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823 "2017-10-14T15:22:54Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [October 14, 2017, 3:22pm UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/1 "2017-10-14T15:22:54Z")
Put another way, can the word “proof” be used in science? Or is the word only to be used in mathematics? As an example, Is the following sentence O.K.? **"We have proof the polio vaccine works."** Or should it be stated, **"We have overwhelming evidence the polio vaccine works."** If the word “proof” is to only be used in mathematics, is in incorrect to say we have proof the Earth goes around the Sun? (Borrowing the theme from a recent thread of mine.) ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [October 14, 2017, 3:33pm UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/2 "2017-10-14T15:33:51Z")
To “prove” something in science—or in a court of law—doesn’t mean the same thing as to prove a mathematical theorem. But as long as we’re aware of the distinction, I don’t see a problem with using the word in more than one way. ---
**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\ **Post date:** [October 14, 2017, 3:34pm UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/3 "2017-10-14T15:34:22Z")
If “cause” can be shown, then “proof” is pretty much shown also. The definition of cause is (roughly) if there is only one difference between a success or a failure in the experiment, then that one, sole, lone factor must have caused the success (or its absence caused the failure.) Medical, psychological, sociological, and economic research is tough, because you can almost never isolate all extraneous factors and limit an experiment to only one key difference. In sciences like these, proof is extremely difficult to demonstrate. But in the world of hard physics, where you can build a particle accelerator and control all the variables, cause (and proof) are possible. There’s also a kind of legal standard of “reasonable doubt.” It is no longer reasonable to doubt evolution or relativity. If you insist on being pedantic, then, no, they aren’t “proven” in an absolute sense – but neither is the existence of the material world. It could all just be a dream/hallucination/illusion/sim. Where along this spectrum from pragmatism to paranoia do you want to get off the tram? ---
**Author:** ![Aufgeblassen](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aufgeblassen/32/7321_2.png) [@Aufgeblassen](https://boards.straightdope.com/u/Aufgeblassen)\ **Post date:** [October 14, 2017, 3:38pm UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/4 "2017-10-14T15:38:52Z")
It has been pretty much proven if you shoot an arrow into the sky, it will come back down to the ground. ---
**Author:** ![filmstar-en](https://avatars.discourse-cdn.com/v4/letter/f/50afbb/32.png) [@filmstar-en](https://boards.straightdope.com/u/filmstar-en)\ **Post date:** [October 14, 2017, 3:53pm UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/5 "2017-10-14T15:53:54Z")
The Scientific method is all about disbelief. There are no absolutes. There are theories that best fit the evidence we have available. If some new evidence turns up, the theory may be replaced with another that is a better fit. But you have to be careful the evidence is consistent and experiments are reproducible. “We have overwhelming evidence the polio vaccine works.” fits This causes a problem for people who are looking for absolutes, like fearful parents. Maths has theorems and proofs. Unless it is statistics, which can be used to lie.:dubious: ---
**Author:** ![AI\_Proofreader](https://avatars.discourse-cdn.com/v4/letter/a/8dc957/32.png) [@AI\_Proofreader](https://boards.straightdope.com/u/AI_Proofreader)\ **Post date:** [October 14, 2017, 4:11pm UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/6 "2017-10-14T16:11:52Z")
> [@Aufgeblassen](#): > > It has been pretty much proven if you shoot an arrow into the sky, it will come back down to the ground. …as long as you don’t design it to survive atmospheric friction and detonate a nuclear bomb underneath it. Or fire it from an electromagnetic rail launcher many kilometers long built on a mountain at the equator, with enough G’s to reach escape velocity. ---
**Author:** ![AI\_Proofreader](https://avatars.discourse-cdn.com/v4/letter/a/8dc957/32.png) [@AI\_Proofreader](https://boards.straightdope.com/u/AI_Proofreader)\ **Post date:** [October 14, 2017, 4:19pm UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/7 "2017-10-14T16:19:32Z")
The wonderful thing about science \*is the fact that there are no proofs. The more we know, the more we find interesting exceptions to the rules. And in some cases whole fields of study where the rules simply don’t apply anymore. Try to apply laws of physics that work perfectly for large objects to quantum particles, and your predictions will be way off. Try to predict how a planet will move based on quantum physics, and you’ll also be way off. Maybe they’ll find a unified field theory that correctly accounts for both some day, but there will continue be new discoveries that turn “always” into “usually.” ---
**Author:** ![The\_Other\_Waldo\_Pepper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/the_other_waldo_pepper/32/12370_2.png) [@The\_Other\_Waldo\_Pepper](https://boards.straightdope.com/u/The_Other_Waldo_Pepper)\ **Post date:** [October 14, 2017, 4:21pm UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/8 "2017-10-14T16:21:23Z")
Doesn’t it depend on how you phrase it? Return now to those thrilling days of yesteryear when someone may have weighed in with confidence on the alleged impossibility of splitting an atom – only for _that_ to then get disproven when someone else, well, does so. Which means that, okay, yes, at that point, folks then had to revise their conclusions and come up with a model that better fit the facts being observed – but, put another way, does that mean we’d proven that some atoms _can_ be split? IIRC, there was a piece in the New York Times back when that – by expressly relying on the accepted scientific wisdom of the day – scoffed at the idea of futuristic rockets leaving the atmosphere to function in outer space. In a manner of speaking, that was disproven; but, in a manner of speaking, wasn’t something _proven?_ ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [October 14, 2017, 4:48pm UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/9 "2017-10-14T16:48:05Z")
Logically, a proof can be perfectly valid but lead to a false conclusion if the premises it’s based on are incorrect. In science, you might have to revise your premises if new evidence comes along. Pure mathematics doesn’t have this problem, because the postulates are just _assumed_ true. > [@Bertrand Russell](#): > > Pure mathematics consists entirely of assertions to the effect that, if such and such a proposition is true of anything, then such and such another proposition is true of that thing. It is essential not to discuss whether the first proposition is really true… > [@Albert Einstein](#): > > As far as the laws of mathematics refer to reality, they are not certain, and as far as they are certain, they do not refer to reality. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [October 14, 2017, 5:16pm UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/10 "2017-10-14T17:16:15Z")
> [@Crafter\_Man](#): > > If the word “proof” is to only be used in mathematics, is in incorrect to say we have proof the Earth goes around the Sun? (Borrowing the theme from a recent thread of mine.) This depends more on the meaning of “proof” than anything to do with science. A couple definitions from Merriam Webster: > [@](#): > > 1 a :the cogency of evidence that compels acceptance by the mind of a truth or a fact > b :the process or an instance of establishing the validity of a statement especially by derivation from other statements in accordance with principles of reasoning > > … > > 3 :something that induces certainty or establishes validity By the common definition of “proof,” yes, we can say that propositions in science have been proved, with the recognition that we can never have 100% certainty about anything. In criminal justice, we say that someone’s guilt has been proved, even though our certainty is much less than that in many cases in science. ---
**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\ **Post date:** [October 14, 2017, 6:30pm UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/11 "2017-10-14T18:30:21Z")
> [@AI\_Proofreader](#): > > . . . Try to predict how a planet will move based on quantum physics, and you’ll also be way off. . . . Well, to be horribly persnickety, no, you’ll get really good answers. There’s absolutely no reason you can’t calculate, say, the uncertainty in the momentum of the earth taken as a single mass. Of course, the results are so close to zero that God himself couldn’t see the difference. It’s sort of like calculating the National Debt using Gold atoms as the currency. Quick, what’s two plus two, to 400 significant digits? ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [October 14, 2017, 6:54pm UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/12 "2017-10-14T18:54:49Z")
> [@Trinopus](#): > > But in the world of hard physics, where you can build a particle accelerator and control all the variables, cause (and proof) are possible. > > There’s also a kind of legal standard of “reasonable doubt.” It is no longer reasonable to doubt evolution or relativity. But you must do the experiments over the entire range of possible variables. By your criteria, proving Newton’s Laws is easy - and often done. But the assumption was they applied over all values of velocity, but that experiment was never done, and so the “proof” of them was not valid. You also have the accuracy problem, so the small discrepancies that could theoretically be noticed were well within experimental error. I prefer preponderance of evidence myself. ---
**Author:** ![Aufgeblassen](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aufgeblassen/32/7321_2.png) [@Aufgeblassen](https://boards.straightdope.com/u/Aufgeblassen)\ **Post date:** [October 14, 2017, 7:14pm UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/13 "2017-10-14T19:14:06Z")
> [@AI\_Proofreader](#): > > …as long as you don’t design it to survive atmospheric friction and detonate a nuclear bomb underneath it. Or fire it from an electromagnetic rail launcher many kilometers long built on a mountain at the equator, with enough G’s to reach escape velocity. Which is true in most all cases. :rolleyes: ---
**Author:** ![SamuelA](https://avatars.discourse-cdn.com/v4/letter/s/c77e96/32.png) [@SamuelA](https://boards.straightdope.com/u/SamuelA)\ **Post date:** [October 14, 2017, 7:54pm UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/14 "2017-10-14T19:54:39Z")
No. Science is about gathering and compiling evidence for a hypothesis. However, if the evidence supports a hypothesis overwhelmingly, with no credible examples of it not being true, you would be a stupid being if you did not assume the hypothesis was true in your decision making. That’s what we mean by “prove”. Nothing can actually be proven, but assuming the hypothesis supported by an overwhelming majority of the evidence is true is _useful_. Assume the theories behind combustible gas expansion are true, and you can design a better engine. Assume the theories behind crop rotation are true, and you are more likely than not to grow more food on your farm. Assume the theory that exercise increases your life and health-span, and you’ll probably live longer if you do it. Assume the theory behind CO2 heating up the planet is true, and you’ll probably have a better future if you try to reduce how much of it you pump into the atmosphere. Nothing is certain, but using the most likely to be true model of the world means your outcome is statistically going to be better. ---
**Author:** ![allotrope](https://avatars.discourse-cdn.com/v4/letter/a/edb3f5/32.png) [@allotrope](https://boards.straightdope.com/u/allotrope)\ **Post date:** [October 14, 2017, 9:22pm UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/15 "2017-10-14T21:22:58Z")
There \*\*\*are \*\*\*scientific proofs aren’t there? I’m thinking of things like [Bell’s theorem](https://en.wikipedia.org/wiki/Bell%27s_theorem) and the [PBR theorem](https://en.wikipedia.org/wiki/PBR_theorem). Granted that there are certain things that might be assumed for the purposes of those proofs but that’s really no different than axioms in math. As an aside I’d also mention that there’s a difference between truth and completeness. Something can be true but incomplete. Take Newtonian dynamics for example. It’s true to the extent that certain underlying conditions are met but not otherwise. For example, it didn’t accurately describe the orbit of Mercury. ---
**Author:** ![Dropo](https://avatars.discourse-cdn.com/v4/letter/d/ce7236/32.png) [@Dropo](https://boards.straightdope.com/u/Dropo)\ **Post date:** [October 14, 2017, 9:27pm UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/16 "2017-10-14T21:27:26Z")
Science is about probabilities. After repeated experiments, if Result X comes up repeatedly, it is probable that Result X is factual. But it is also important to remember that facts in science are always subject to being proved wrong. This is why Science calls them “theories.” I think it is more useful to consider those “facts” which are not capable of being proved right or wrong, so as to exclude them from the realm of Science. For this purpose, there is Falsification: > **[Falsifiability](https://en.wikipedia.org/wiki/Falsifiability)** > > Falsifiability is a deductive standard of evaluation of scientific theories and hypotheses, introduced by the philosopher of science Karl Popper in his book The Logic of Scientific Discovery (1934).\[B\] A theory or hypothesis is falsifiable (or refutable) if it can be logically contradicted by an empirical test. > Popper proposed falsifiability as the cornerstone solution to both the problem of induction and the problem of demarcation. He insisted that, as a logical criterion, falsifiability is ... ---
**Author:** ![SamuelA](https://avatars.discourse-cdn.com/v4/letter/s/c77e96/32.png) [@SamuelA](https://boards.straightdope.com/u/SamuelA)\ **Post date:** [October 14, 2017, 9:46pm UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/17 "2017-10-14T21:46:28Z")
> [@allotrope](#): > > There \*\*\*are \*\*\*scientific proofs aren’t there? I’m thinking of things like [Bell’s theorem](https://en.wikipedia.org/wiki/Bell%27s_theorem) and the [PBR theorem](https://en.wikipedia.org/wiki/PBR_theorem). Those theorems exist in a purely mathematical world. They say, “in a simplified world subject to these rigid rules, given that these rules are invariant, then _this_ is true”. You can’t use such proofs for things in the real world with the same certainty, because we do not have absolute certainty of what the rules are in the real world. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [October 14, 2017, 9:57pm UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/18 "2017-10-14T21:57:49Z")
I doubt there are many scientists who would object to the use of the word “proof”. It’s just understood that the term has a different meaning in science than it does in math. Just as the term “momentum” has a different meaning in politics than it does in physics. No one thinks that a campaign gaining “momentum” means that its mass x velocity is increasing. Personally, I think it would be more helpful if we paid better attention to the use of the terms “hypothesis” and “theory” when discussing scientific topics. The latter is too often used to mean the former. ---
**Author:** ![allotrope](https://avatars.discourse-cdn.com/v4/letter/a/edb3f5/32.png) [@allotrope](https://boards.straightdope.com/u/allotrope)\ **Post date:** [October 15, 2017, 1:06am UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/19 "2017-10-15T01:06:10Z")
> [@SamuelA](#): > > Those theorems exist in a purely mathematical world. They say, “in a simplified world subject to these rigid rules, given that these rules are invariant, then _this_ is true”. > > You can’t use such proofs for things in the real world with the same certainty, because we do not have absolute certainty of what the rules are in the real world. I’m not sure that’s completely accurate. Bell’s theorem, according to Wikipedia, states “No physical theory of [local hidden variables](https://en.wikipedia.org/wiki/Local_hidden_variable_theory) can ever reproduce all of the predictions of quantum mechanics.” That sounds like it’s talking about the real world to me. PBR states “that either the [quantum state](https://en.wikipedia.org/wiki/Quantum_state) corresponds to a physically real object and is not merely a statistical tool, or else all quantum states, including non-[entangled](https://en.wikipedia.org/wiki/Quantum_entanglement) ones, can communicate by [action at a distance](http://javascript%3Cb%3E%3C/b%3E:void(0)).” Again, that sounds like it’s talking about the real world and more specifically is saying that the wave function describes a real phenomenon. ---
**Author:** ![Llama\_Llogophile](https://avatars.discourse-cdn.com/v4/letter/l/49beb7/32.png) [@Llama\_Llogophile](https://boards.straightdope.com/u/Llama_Llogophile)\ **Post date:** [October 15, 2017, 2:24am UTC](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823/20 "2017-10-15T02:24:25Z")
The scientists I have known always spoke in terms of evidence rather than proof. Here’s part of [James Randi lecture](https://www.youtube.com/watch?v=qWJTUAezxAI) where he talks about being unable to “prove” a negative, and what sort of evidence we consider convincing. No reindeer were hurt during this lecture. [Next page](https://boards.straightdope.com/t/can-anything-be-proved-in-science/798823.md?page=2)