[Hitch]

Originally Posted by ApK

Seriously? Let's start with obvious:

My 17 year old daughter didn't kill JFK.
I'll bring in historians, medical doctors and physicists to prove JFK died in 1963, she wasn't born then, and time travel isn't possible, so she couldn't have done it . QED.

Yes, because that's a physical impossibility. That is, for all intents and purposes, "proof." That's not at all what people mean. You're proving an alternative. That means that proof exists. You aren't in fact proving the negative--you've proven that someone else, alive in 1963, did do the deed. Even if you don't know who that person is.

Slightly more relevant to the situations I'm referring to:
My client didn't shoot the victim.
The victim was shot at noon by a thin, short white person, as shown on the security footage and corroborated by the three cops who witnessed it.
My client is a 7 foot tall 400 pound black person who at noon was in chains, in this court room, in your presence, your honor, and so could not have done it. QED.

Yes, and again, you've made up some scenario in which the accusation would never occur. That doesn't do it, either. Change it so that there's any remote likelihood that it might. What if the person who was shot at noon was shot by someone who is your client's spitting image. Your client is not on video, not on tape. Then what? Prove that he didn't do it. You do not have proof that your client didn't do it. You don't have evidence that someone else did. Now, prove he didn't.

The point is..."proof" means just that. EVIDENCE that can absolutely show that the question under consideration cannot have happened. When you solve the matter by coming up with the alternate scenario, you have not proven a negative--you have proven a positive, that this other perpetrator DID perform the deed.

When people talk about not being able to prove a negative, it's not in some cute scenario in which the reality is easily disputed; it's when the only avenue is doing just that--proving that X did not occur.

From there, we just get in to various levels of near-certainty, still well beyond any reasonable doubt.

Yes, but again, anybody can make up some scenario in which "proof" is easily gathered in the positive for an alternate option, e.g., John Doe was in Tokyo, demonstrably (proof!) when Jane Smith was shot. That IS proof. What you're doing is saying that if there's positive proof that something DID happen, that it's the equivalent of proof that a negative didn't happen. That's not the same legal or logical argument.

For many, many, many things, for something to have happened, some other things must have also happened or not happened.
If X had happened, it would have precluded Y. We can prove Y, so we've disproved X.
Like Sherlock Holmes observed, a person can't pass through a room without taking or leaving something. Show enough evidence, or lack thereof, of enough of those somethings and you meet any burden of proof.

Actually, Locard's theorem, but...fine, not sure how you think that applies. The entire point of Locard is that if the person wasn't there...there won't be any proof that he was NOT. Only that you cannot prove that he WAS. Two different things. Trust me, no court in the world would accept the idea that you didn't leave any hair, fibers, etc. in John Doe's apartment as "proof" that you weren't there. Evidence that you may not have been there? Sure...but not proof.

The kid didn't eat the cookie. The cookie still there, intact. So it can't can't have been eaten, by him or anyone. QED

Again...to test out the argument, you have to have a scenario in which you do not have proof in the alternative. Nobody is going to accuse yon brat of eating the cookie when it's already still intact, now, are they? So, coming up with something like that, beyond being frivolous, does not solve the logic issue.

In your shelffish example, restaurant security footage shows everything the victim touched, ate or drank, and lab tests show no trace of shellfish on any of it or anywhere in our vegan restaurant. Is that enough proof?

Actually, again, it's not "proof." That's evidence. Not the same thing. There's evidence that leads one to believe that it's likely not the restaurant, but no proof that clearly indicates that they didn't do the deed. It's inference and deduction, but not proof. Is it probably 99% good enough? Yes, sure, for a real case in a real world with real video footage, assuming it exists.

"Proof" is indisputable evidence that something is true (or not, let's say for the sake of argument); "evidence" is just something that leads you to believe that something is, or is not, true. They are not the same thing.

Everything you've said in this post--is evidence. NOT proof. Sorry if you think this is hair-splitting, but it's not. You're trying to take apart a logic argument by conflating the two.

Ask yourself how this is proven, if/when the kitchen doesn't have a single camera in sight. What happens then? What's the evidence, or the proof, then?

ETA: "You can't prove a negative?" Really? Prove it. Ha! Logical paradox, sucka!
(Ooh... I like that. I'll need to use that line in a story sometime.)

Evidence is one thing. PROOF is another. Sorry but there it is.

I just watched the surprisingly funny "National Lampoon's Loaded Weapon 1." It parodied that with a spoof of Dirty Harry's "I know what you're thinking: Did I shoot 6 shots, or only 5?" with the character saying "Did I shoot 174 shots, or only 173?"

I'm glad you enjoyed it.

Hitch