It’s more a question about how you want to think about things, I think. If we say that |dead> and |alive> are pure quantum states, and the cat is in some superposition |dead> + |alive> (with appropriate coefficients I leave out for convenience), then it’s correct to say ‘the cat is not alive’, since |dead> + |alive> is a different quantum state from |alive>. However, both the states |dead> and |alive> are present in the superposition in some sense, so I wouldn’t say that ‘the cat is both dead and alive’ is strictly wrong, either; add to that the fact that in common parlance, ‘not alive’ = ‘dead’, since we tend not to have a third alternative, and it’s easy to say what the physicist on the radio said, and mean the same thing you mean.
As indeed is the cat. The qualification about not being “strongly coupled with his environment” functions basically, as weasel words. Your scientist was basically saying “quantum weirdness occurs, except when it does not (which is, in fact, almost always).” In other words, he was bullshitting.
Is a cat any more of a quantum particle than I am?
(Also, what **Chronos **said.)
I’d give the same answers in that case–false, false, true, true. It’s not heads, and it’s not tails.
Yeah, I agree now. I actually tried to delete that last bit after reading Half Man Half Wit’s reply, but it was too late.
The answer to each of the OP’s 4 propositions is “unknowable” for reasonable definitions of “alive” and “dead”.
If we assume that “alive” & “dead” describe a) Mutually exclusive states in the non-quantum world, and b) There are no other states of the cat’s aliveness (for lack of a better word) attribute, then …
“Alive” and “not dead” are synonymous. Just as “zero” and “not one” are equivalent in binary math. Ditto “dead” and “not alive”.
So whatever answer you choose to give for one of those pairs determines the answer of its contrapositive. And since we’ve asserted that “alive” and “dead” are negations of each other, then the chosen value for any one value determines the other three.
For an ordinary cat in an ordinary non-poisonous box in another room which you cannot see, the right answer to all 4 questions is “unknown.” And when you go look, the cat’s state is obvious and the other 3 values are determined by Boolean logic, not QM.
The whole point of superposition is that things which must, in the classical world, be mutually exclusive (or more generally determined by one another in some causal chain) can be in indeterminate states under QM.
And once superposition enters the game, the only right answer is “unknowable”. Period, end of syllogism.
Said another way, to assert that not-alive (or not-dead) is true is to assert you have knowledge of the srate of the cat. Which you cannot have while it is superposed.
Also, to assert that alive (or dead) is false is to assert you have knowledge of the srate of the cat. Which you cannot have while it is superposed.
And to assert that my two assertions just above are not completely equivalent is to assert that dead and alive are not mutually-exclusive-and-mutually-determined within the *classical *world, not the QM world.
At least that’s my lay-but-interested understanding.
Silly people! The cat is half-dead, of course!
The cat is only mostly dead.
For your next experiment, affix a piece of buttered toast (buttered-side up) onto a cat’s back and drop it from a height. Levitation! 
You both are and are not saying the right thing, until someone reads the thread.
Note that the mere idea of a situation where one does not know whether a cat in a box is dead or alive, and the question as to whether or not, till this veil of ignorance is lifted, the cat should be considered as having a definite state or instead as merely being in some kind of superposition, etc., have nothing intrinsically to do with the empirically discovered theory of quantum mechanics; in themselves, these are simple philosophical topics which could well be explored regardless of whether or not particular scientific experiments ever came out one way or another. Much popular discussion of quantum mechanics never gets beyond these sorts of vagaries. Unfortunately, this means much popular discussion of quantum mechanics never actually discusses quantum mechanics, per se, at all (perhaps because people are shy to speak of mathematical details? But to avoid mentioning math entirely is to avoid mentioning the actual relevant scientific laws/theories; and if one never discusses these, then whatever one is doing, it’s got nothing to say about or do with the science of the matter at all). Let us not be like that. Let us actually introduce some specific details which are characteristically quantum mechanic. Let us actually review some brute experimentally discovered results, which had they turned out differently would not have caused us to adopt quantum mechanics as a physical theory. Noncommuting observables, destructive interference, violations of Bell’s inequality, whatever the relevant results are, and why they are relevant.
Only… I am not a physicist. Indeed, my level of scientific knowledge is at times embarrassingly low. Many people on these boards are physicists, and are good at explaining things to boot. Perhaps they should present the relevant results instead of me. But, if no one else steps forward, I’ll give my own slight understanding of the matter. The main thing is that I just want to see discussion of Schroedinger’s cat that actually touches on quantum mechanics, rather than merely the perfectly classical idea of an unknown in a box (albeit we could still philosophize in the latter case; we should just recognize that this is a discussion we could have orthogonal to the truth of quantum mechanical theory).
Go for it. I’ve always understood contemporary discussions of The Cat to be merely illustrative anyway–the cat is supposed to “stand for” a particle.
After all, as several have pointed out above in the thread, shouldn’t we treat the cat as an observer itself?
Really what I’m wondering about is what to say about particles, I was just using the familiar illustration of Schroedinger’s Cat as a way to have that discussion.
I’ve heard some people say sometimes that quantum physics requires us to let go of the law of non-contradiction–that sometimes, in quantum physics, the same thing is both true and false of a particle. I’ve never been able to bring myself to buy this–even though I’ve occasionally even heard some physicists say it!–and it’s always seemed to me that things behave perfectly classically logically down there, as long as we understand superposition to be a state distinct from any of the states it is a superposition of.
But hearing a physicist say things like “the editor is both there and not there at the same time” made me want to get into that issue again.
The cat isn’t supposed to stand for a particle. The whole point of talking about Schroedinger’s Cat is that it’s a macroscopic entity in a quantum superposition. Lots of people who have no problem with a particle being in a superposition of spin up and spin down balk at the idea of a macroscopic cat being in a superposition of dead and alive.
There can be multiple observers, some in superposition relative to others. From the point of view of the cat, it’s an observer, and definitely alive or dead. Still, from the point of view of an observer outside the box, the cat is in a superposition.
Assumption b is where you go wrong. I think Half Man Half Wit’s explanation is the best, but maybe consider the coin flip analogy in my post above that. The coin can be in the state heads, tails, or not yet flipped.
I could be wrong, but I was pretty sure that things’ being in superposition or not is not observer relative. Would enjoy seeing a cite about it though.
Won’t someone just switch out the cyanide gas for high explosives and be done with that damn vermin?
As I point out in the second part of my post.
The point of disagreement I see between you and I is this:
You in effect assert that “not heads” includes “not yet flipped”. I would argue that “not known to be heads” does include “not yet flipped”. But “not heads” is a different idea which is strictly equal to “tails”. And is therefore inapplicable to discussing the case of “not yet flipped”.
The bigger point overall is the one made by Indistiguishable: that it’s easy for any of us to be sucked into arguing philosophy of the meaning of “knowledge of a fact”, rather than arguing QM. The first part of my post that you cite falls at least partly into that trap. As does discussions of coin flips.
To me, the real crux of what I believe to be the correct argument is this (slightly re-stated from my post above)
And that is not a matter of philosophy of knowledge. It’s a matter of the QM definition of the concept of superposition.
Can we know that something is superposed?
You can choose to define heads however you want, and that’s a semantics question, whether you’re discussing QM or not.
In that vein, though, I would argue that taking not heads as strictly equivalent to tails and vice-versa isn’t a particularly good definition. What if the coin I’m holding, I instead melt or burn before I get around to flipping it? Does that count as heads or tails?
Not at all! If you READ Schrodinger, it’s “Half dead”, not “Mostly dead”. Silly Human…