# Yes, dammit, one CAN prove a fucking negative **URL:** \ **Category:** The BBQ Pit\ **Created:** [July 23, 2005, 9:08pm UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846 "2005-07-23T21:08:37Z")\ **Posts on this page:** 20\ **Page:** 4
**Author:** ![Gfactor](https://avatars.discourse-cdn.com/v4/letter/g/9de053/32.png) [@Gfactor](https://boards.straightdope.com/u/Gfactor)\ **Post date:** [July 26, 2005, 3:58pm UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/61 "2005-07-26T15:58:51Z")
> [@Finagle](#): > > Please read my post again. I said I wasn’t making assumptions about \* all \* sunflowers. The perceptual assumptions I’m forced to make about my own sunflower due to my sensory apparatus aren’t particularly interesting in the context of this argument. Aren’t you assuming something about all sunflowers in concluding that what you are observing is a sunflower? > [@](#): > > If you want to go down this path, then you basically are demonstrating the whole “You can’t prove a negative thing” because you leave me with no tools to prove that it isn’t a sunflower, that I’m not hallucinating, and so on. (Of course, in this case, “You can’t prove a negative” is just a subset of “You can’t prove anything.”) So, should we just throw up our hands and give up? And if so, does that mean that those assertions are wrong, or simply that you aren’t interested in discussing them? > [@](#): > > Any philosophical debate can be derailed by an appeal to the fallibility or subjective nature of the senses. Nah. Maybe scientific debates. There are plenty of philosophical debates that don’t involve the necessity of perfect knowledge. ---
**Author:** ![Liberal](https://avatars.discourse-cdn.com/v4/letter/l/848f3c/32.png) [@Liberal](https://boards.straightdope.com/u/Liberal)\ **Post date:** [July 26, 2005, 4:18pm UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/62 "2005-07-26T16:18:22Z")
> [@Gfactor](#): > > You might say it is definitional, or a tautology even. We aren’t adding anything to the system by repeatedly examining the sum of 1 + 1. In effect, we aren’t doing science at all. Agreed. As a matter of fact, tests conducted on Special Relativity, for example, did not confirm the theory to be true. The theory was true the moment Einstein drew his final deductive inference. ---
**Author:** ![Finagle](https://avatars.discourse-cdn.com/v4/letter/f/b19c9b/32.png) [@Finagle](https://boards.straightdope.com/u/Finagle)\ **Post date:** [July 26, 2005, 6:25pm UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/63 "2005-07-26T18:25:15Z")
> [@Liberal](#): > > Agreed. As a matter of fact, tests conducted on Special Relativity, for example, did not confirm the theory to be true. The theory was true the moment Einstein drew his final deductive inference. Huh? The theory may have been true in a syntactic deductive sense, but as far as anyone knowing or believing it was true, there was considerable heavy lifting to be done. Deduction is only as sound as your set of premises allow it to be, and in the \* real \* world, you have a couple of problems: a. You don’t know that your premises are sound. b. You don’t know that they are complete. From your very own citation regarding Karl Popper: "With Einstein’s theory the situation was strikingly different. Take one typical instance — Einstein’s prediction, just then confirmed by the finding of Eddington’s expedition. Einstein’s gravitational theory had led to the result that light must be attracted by heavy bodies (such as the sun), precisely as material bodies were attracted. As a consequence it could be calculated that light from a distant fixed star whose apparent position was close to the sun would reach the earth from such a direction that the star would seem to be slightly shifted away from the sun; or, in other words, that stars close to the sun would look as if they had moved a little away from the sun, and from one another. " (That’s assuming you can actually speak of a theory as “true” which I’ve always heard was sort of frowned on. I thought the nicest thing you can say about a theory is that it has predictive power and doesn’t conflict with any known observations.) ---
**Author:** ![Liberal](https://avatars.discourse-cdn.com/v4/letter/l/848f3c/32.png) [@Liberal](https://boards.straightdope.com/u/Liberal)\ **Post date:** [July 27, 2005, 10:48am UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/64 "2005-07-27T10:48:58Z")
Popper’s concern was not about whether a theory was true, but whether it was _scientific_. The point I’ve been trying to make with you for the past three days is that those two things — true and scientific — are not synonyms. As for Einstein’s premises, he used two: (1) the speed of light in a vacuum is constant, and (2) physical law is the same everywhere in the universe. Note that you cannot test either of these scientifically — you would have to monitor the entire continuum of spacetime. Finally, it might be of interest to note that falsification (Popper’s identifying tag for science versus pseudoscience) is itself an analytic (like truth) and therefore is itself not falsifiable. So, the entire validity of science rests on an analytic axiom. ---
**Author:** ![tnetennba](https://avatars.discourse-cdn.com/v4/letter/t/7993a0/32.png) [@tnetennba](https://boards.straightdope.com/u/tnetennba)\ **Post date:** [July 27, 2005, 12:03pm UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/65 "2005-07-27T12:03:22Z")
Scientists no longer believe that something has to be falsifiable to be scientific – at least according to Wikipedia. ---
**Author:** ![SentientMeat](https://avatars.discourse-cdn.com/v4/letter/s/43a26b/32.png) [@SentientMeat](https://boards.straightdope.com/u/SentientMeat)\ **Post date:** [July 27, 2005, 1:11pm UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/66 "2005-07-27T13:11:57Z")
Be careful with Wikipedia, **cricetus**. Robert McHenry, former editor of Encyclopedia Britannica, likened the “faith-based encyclopedia” to a public toilet: you’re never sure who used it last. It’s fine as a source to summarise what can be found in other sources, but beware of claiming it as an authority in itself. In this case, the strict falsifiable=scientific criterion is sometimes relaxed in the case of new theories which are based on old ones which have withstood rigorous testing (“true _beyond reasonable doubt_”, or “not shown false even despite tests which were _almost impossible to pass_” perhaps) but are such that the falsifiable consequences are not **yet** apparent, or the tests are not **yet** technologically possible. Thus the term [protoscience](http://en.wikipedia.org/wiki/Protoscience) is often used to distinguish it from [pseudoscience](http://en.wikipedia.org/wiki/Pseudoscience). ---
**Author:** ![Liberal](https://avatars.discourse-cdn.com/v4/letter/l/848f3c/32.png) [@Liberal](https://boards.straightdope.com/u/Liberal)\ **Post date:** [July 27, 2005, 1:41pm UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/67 "2005-07-27T13:41:42Z")
Sentient, since you’re here (and thank you for stopping in, by the way), would you mind explaining exactly why falsifiability is so critical to empirical tests? Your expository skills are much better than mine, and I can’t seem to get across the point that science predicts but does not predicate. ---
**Author:** ![SentientMeat](https://avatars.discourse-cdn.com/v4/letter/s/43a26b/32.png) [@SentientMeat](https://boards.straightdope.com/u/SentientMeat)\ **Post date:** [July 27, 2005, 2:32pm UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/68 "2005-07-27T14:32:39Z")
It seems that the term “empirical proof” is the bee in this particular bonnet. You are using the word “proof” in the strict mathematical or analytical sense, **Fin** is using it as in the phrase “proof beyond reasonable doubt”, _ie._ the standard of the ‘statistical’ evidence one sees in a court of law. I’m loathe to step into such semantics, really. Scientists, whoever they are, set forth linguistic propositions having varying possible correlations to somehow-sensed data: this is, IMO, the nature of “truth” and “falsity”. If (for whatever reason) no such correlation can be made, the liguistic proposition is tagged by the label “unscientific” according to a chap called “Karl”. Even if such a correlation _is_ possible, we can only _trust_ that our correlation modules are working correctly and that the same correlation result will be returned in future: thus, there is no _absolute_ “truth”. Empiricism is about observations (from whatever sensory input). Truth is about the correlation between the observation and the linguistic sentence you set up: it is not the observations _themselves_. This is a debate I’d prefer to set up myself rather than jump into someone else’s - I could find stuff me and **Fin** disagree on (and I wholeheartedly agree with **Lib** ’s OP, despite understanding the gist of what “you can’t prove a negative” is _supposed_ to mean), and I could debate **Lib** on some issues (I think defining science _solely_ as a methodology is overly restrictive: when I speak of _cognitive science_ or _materials science_ I mean not just the methods but the _body of working conclusions derived thereby_. I think that “science’s answers” or “a scientific fact” are useful shorthand for what _has_ been tested rigorously compared to what hasn’t, despite me not going as far as allowing “absolute scientific truth” or the like.) I will now pick the fence-splinters from my behind. 🙂 ---
**Author:** ![Finagle](https://avatars.discourse-cdn.com/v4/letter/f/b19c9b/32.png) [@Finagle](https://boards.straightdope.com/u/Finagle)\ **Post date:** [July 27, 2005, 2:54pm UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/69 "2005-07-27T14:54:55Z")
Sentient Meat, as long as you’re willing to act as an intepreter between our separate universes, can you please explain what Liberal meant by “Agreed. As a matter of fact, tests conducted on Special Relativity, for example, did not confirm the theory to be true. The theory was true the moment Einstein drew his final deductive inference.” This makes no sense to me in a number of ways. The first, of course, is that we don’t actually consider any theory to be “true”. I \* think \* that Liberal is using the term “true” in the sense of “logically sound”. But he might also be using “true” in the sense of some Platonic ideal of truth – I dunno. I’d like to know why the theory of Special Relativity was true “the moment Einstein drew his final deductive inference” while, for example, the Phlogiston theory was not. ---
**Author:** ![SentientMeat](https://avatars.discourse-cdn.com/v4/letter/s/43a26b/32.png) [@SentientMeat](https://boards.straightdope.com/u/SentientMeat)\ **Post date:** [July 27, 2005, 3:27pm UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/70 "2005-07-27T15:27:08Z")
> [@Fin](#): > > can you please explain what Liberal meant by > > “Agreed. As a matter of fact, tests conducted on Special Relativity, for example, did not confirm the theory to be true. The theory was true the moment Einstein drew his final deductive inference.” > > …I _think_ that Liberal is using the term “true” in the sense of “logically sound”. Yes. _Given_ the truth of the two premises, Einstein’s mathematical treatise yielded such conclusions as E=mc[sup]2[/sup] (equivalence of mass and energy) and t1= t0/(1-v[sup]2[/sup]/c[sup]2[/sup]) (time dilation), which were true if the premises were true given the logical validity of Einstein’s mathematical manipulations. Just to clear up a nitpick, Eddington’s observations pertained to the consequences of Einstein’s _general_ theory of relativity, which incorporated further premises regarding gravity in addition to the two of special. But ultimately, what those observation did was simply provide evidential support for the truth of _those original premises_, rather than the “truth” of Einstein’s _manipulations thereof_. Put simply, his _conclusions_ couldn’t have been false, but they could have demonstrated a situation in which the _original premises_ were false, in which case the logical consequences of some _other_ premises (_eg._ the existence of phlogistons) might have been explored. ---
**Author:** ![SentientMeat](https://avatars.discourse-cdn.com/v4/letter/s/43a26b/32.png) [@SentientMeat](https://boards.straightdope.com/u/SentientMeat)\ **Post date:** [July 27, 2005, 3:31pm UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/71 "2005-07-27T15:31:21Z")
Sory, to clarify, Einsteins conclusions were logically [valid](http://en.wikipedia.org/wiki/Validity). Their logical [soundness](http://en.wikipedia.org/wiki/Soundness) depended on the truth of the original premises. Eddington’s observations provided an extremely rigorous test of those original premises, which they came through against all odds: they could still not be said to be _true_, but they were not _false_ despite an incredibly difficult test. ---
**Author:** ![js\_africanus](https://avatars.discourse-cdn.com/v4/letter/j/87869e/32.png) [@js\_africanus](https://boards.straightdope.com/u/js_africanus)\ **Post date:** [July 27, 2005, 6:40pm UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/72 "2005-07-27T18:40:55Z")
> [@Loopus](#): > > Whenever someone tells me “You can’t prove a negative,” say, “That’s a negative and therefore cannot be proven.” ---
**Author:** ![Liberal](https://avatars.discourse-cdn.com/v4/letter/l/848f3c/32.png) [@Liberal](https://boards.straightdope.com/u/Liberal)\ **Post date:** [July 27, 2005, 7:54pm UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/73 "2005-07-27T19:54:27Z")
“Something unknown is doing we don’t know what.” — Arthur Eddington ---
**Author:** ![Spiritus\_Mundi](https://avatars.discourse-cdn.com/v4/letter/s/c68b51/32.png) [@Spiritus\_Mundi](https://boards.straightdope.com/u/Spiritus_Mundi)\ **Post date:** [July 27, 2005, 9:17pm UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/74 "2005-07-27T21:17:59Z")
One can prove anything, depending upon one’s axioms. Statements regarding what can and cannot be proven (outside of a rigorously structured debate) should always be understood as a short-hand for making an epistemological generalization. An epistemological generalization, of course, is pretty much useless as proposition in a rigorous debate, but they can be useful when in a conversational exchange. So, I agree wiht the OP. It is quite trivial to prove a negative given the right negative and an appropriate system. But I also feel inclined to give the Buckaroo Bonzai response: “So what? Big deal.” ---
**Author:** ![Liberal](https://avatars.discourse-cdn.com/v4/letter/l/848f3c/32.png) [@Liberal](https://boards.straightdope.com/u/Liberal)\ **Post date:** [July 27, 2005, 9:25pm UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/75 "2005-07-27T21:25:00Z")
Spiritus Mundi! […happy dance…] How have you been? I have mentioned you often, and have missed you sorely. ---
**Author:** ![SlyFrog](https://avatars.discourse-cdn.com/v4/letter/s/a3d4f5/32.png) [@SlyFrog](https://boards.straightdope.com/u/SlyFrog)\ **Post date:** [July 27, 2005, 10:29pm UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/76 "2005-07-27T22:29:33Z")
> [@Liberal](#): > > “Something unknown is doing we don’t know what.” ? Arthur Eddington As we know, There are known knowns. There are things we know we know. We also know There are known unknowns. That is to say We know there are some things We do not know. But there are also unknown unknowns, The ones we don’t know We don’t know. –Donald Rumsfeld ---
**Author:** ![Spiritus\_Mundi](https://avatars.discourse-cdn.com/v4/letter/s/c68b51/32.png) [@Spiritus\_Mundi](https://boards.straightdope.com/u/Spiritus_Mundi)\ **Post date:** [July 27, 2005, 11:28pm UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/77 "2005-07-27T23:28:31Z")
**Lib** (A new nick? You can’t disguise that inimitable style.) I’ve been better; I’ve been worse; but mostly I’ve been insanely busy. I missed this place, but I had to scale back my time to necessities for a while. Thanks for the wam welcome. ---
**Author:** ![wring](https://avatars.discourse-cdn.com/v4/letter/w/838e76/32.png) [@wring](https://boards.straightdope.com/u/wring)\ **Post date:** [July 27, 2005, 11:38pm UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/78 "2005-07-27T23:38:19Z")
> [@Spiritus Mundi](#): > > Thanks for the wam welcome. (since I’m Queen of typos, I won’t make a joke here) funny - I just saw your name and was all thrilled o see you again, too. HI!!! ---
**Author:** ![Spiritus\_Mundi](https://avatars.discourse-cdn.com/v4/letter/s/c68b51/32.png) [@Spiritus\_Mundi](https://boards.straightdope.com/u/Spiritus_Mundi)\ **Post date:** [July 28, 2005, 3:27am UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/79 "2005-07-28T03:27:24Z")
Back at ya. (and I wouldn’t really be back if I didn’t sprinkle in a few typos.) ---
**Author:** ![wring](https://avatars.discourse-cdn.com/v4/letter/w/838e76/32.png) [@wring](https://boards.straightdope.com/u/wring)\ **Post date:** [July 28, 2005, 3:33am UTC](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846/80 "2005-07-28T03:33:30Z")
& weren’t you kind to ignore mine? 😉 [Previous page](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846.md?page=3) [Next page](https://boards.straightdope.com/t/yes-dammit-one-can-prove-a-fucking-negative/313846.md?page=5)