Depends somewhat on the particular negative. We can claim with certainty that dinosaurs are not alive today, even though there are theoretically places that are not sufficiently explored where, in principle, a dinosaur might live. We are well aware that the fossil record is globally consistent and demonstrates the timing of their extinction, as well as the lack of any fossils of dinosaurs since then.
Similarly, I can claim with confidence that a force does not exist in the universe that would allow me to teleport from place to place instantaneously, because such a force would violate many of the known laws of physics.
There are various types of god-beings that cannot exist because of a logical contradiction. An omnipresent entity, for instance, would be always detectable if it had any measurable effect on the world, but no such measurable effect can be observed. If it is not capable of a measurable effect, then it is indistinguishable from not existing.
Other types of negatives are not easily proven. That is why scientists will say things like, “Based on 3478 measurements, there is currently no evidence to support the existence of higher values than those reported here.”
Prove to me you never raped your niece
Be careful with this one though.
By simple analogy. You can prove that there are white crows by finding a single white crow, but to prove that there are no white crows you must conduct an exhaustive search of every corner of the earth and never find a single one and somehow be absolutely certain that you didn’t miss one somewhere.
The only way to be absolutely certain that you didn’t miss something is to be able to look everywhere all at once, otherwise a white crow might evade your notice, and that’s impossible.As such all you can say is there probably aren’t any white crows because we have lots of experience seeing crows and there has been no evidence of one yet.
As such all you can say is there probably aren’t any white crows because we have lots of experience seeing crows and there has been no evidence of one yet.
spoiler
Plenty of crows with albinism exist! Do a quick search for images -
albino crow.https://www.nsnews.com/local-news/rare-albino-crow-rescued-in-north-vancouver-3126073
It’s just an example man.
Similar to the argument Intelligent Design (anti evolutionists) use. They always point to fossil gaps and say “Well, what happened there?” You have no control over what gets fossilized and where you can find them and there will always be a gap somewhere. “Well there is a gap on Tuesday, 67,000,000 BC!” There is no possible way to fill in every imaginable gap with physical evidence vs seeing patterns and development across those gaps.
This is a very good analogy!
Although to be pedantic, there are white crows; there was one living in my neighborhood some years back.
It’s just an example. Mentally edit it to polka-dotted hippopotamuses if it makes ya happy. ;)
The invisible pink unicorn is the traditional atheist approach.
tl;dr for others
A: “I have an Pink Unicorn inside the trunk of my car. It vanishes the moment you try to open the trunk or look at it.”
B: “What? That’s absurd”
A: “I know it exists. It’s up to you to disprove it”
B: “But there is no way one can capture/observe/understand it with any sort of scientific instrument”
A: “Don’t care. Skill issue”
Stop talking shit about me.
I’m not.
Oh yeah? prove it.
If you subscribe to classical logic (i.e., propositonal or first order logic) this is not true. Proof by contradiction is one of the more common classical logic inference rules that lets you prove negated statements and more specifically can be used to prove nonexistence statements in the first order case. People go so far as to call the proof by contradiction rule “not-introduction” because it allows you to prove negated things.
Here’s a wiki page that also disagrees and talks more specifically about this “principle”: source (note the seven separate sources on various logicians/philosophers rejecting this “principle” as well).
If you’re talking about some other system of logic or some particular existential claim (e.g. existence of god or something else), then I’ve got not clue. But this is definitely not a rule of classical logic.
When people colloquially say “you cannot prove a negative” they are usually referring to the fact that absence of evidence can not be used to deduce non-existence of some phenomena (“a negative”), whereas the factual discovery of a phenomena can be used to deduce that the phenomena exists (“a positive”).
They are therefore not referring to formal negation but rather making a point about deductive vs. inductive reasoning and the asymmetry of these two related questions (existence vs. nonexistence).
There is a bit of nuance to add here in that practically speaking you can’t really “discover a fact” by direct observation. But again this is a colloquialism as most laypeople will accept what is directly observable under their noses as factual rather than a noisy data point of one.
I think you are assuming a level of competence from people that I don’t have faith people actually have. People absolutely can and do take “you cannot prove a negative” as a real logical rule in the literal negation sense. This isn’t colloquialism. This is people misunderstanding what the phrase means.
I have definitely had conversations with idiots that have taken this phrase to mean that you just literally cannot logically prove negated statements. Whether folks like you get that that is not what the phrase refers to is irrelevant to why I’m pointing out the distinction.
Sure I can agree with that.
However, I think that is sort of a special case that’s easy to resolve. It only comes up when they are already in the business of learning logical proofs & will likely be looking to learn from someone or a textbook who will most likely clear that up for them…
Chances are that person already has a baseline level of competency in logical thinking, or, if they don’t, they soon will learn and are open to it. They’ve at least additionally already mastered the colloquial meaning of the phrase and are simply a bit overzealous with it’s use (which should be reigned in as you aptly point out).
On the other hand, when people don’t understand “you can’t prove a negative” in social situations unrelated to formal logic, it’s generally observed they are up to their eyeballs in conspiracy thinking and are so lost in magical thinking that they’ve abandoned even informal rule of thumb levels of logic.
Those are truly sad situations with deep (inter)personal, social, and political consequences, especially if they go on to harm others based on their misunderstandings.
Ironically it seems we both have less faith in the competence of others, albeit in different ways lol
Fair points. The latter case is basically where my concern is.
Conversations like this is why Lemmy feels so much more refreshing than Reddit, so thank you for that… I hadn’t realized how desperately I’ve missed the old internet
Hah no worries. Thanks for being so reasonable yourself lmao.
