Harry could still get a false negative. Remember, Harry will feel the impulse to offer a drink to Alice if and only if if Alice is about to be surprised. So not feeling an impulse to offer her a drink would indicate that either that Alice would not be surprised that Voldemort is alive, or that Harry will not actually end up telling her.
Harry could still get a false negative. Remember, Harry will feel the impulse to offer a drink to Alice if and only if if Alice is about to be surprised.
Again, we don’t know that. The soda working in two steps as you seem to suggest (detecting future surprise, then determining whether that surprise is sufficient to cause soda spitting when drunk at the right time) is consistent with what we know about the soda. But that’s not the only possibility consistent with what we know. The soda could also work in a single step and detect whether soda drunk at various points would be spit, without directly detecting surprise at all.
Regardless of the reason for the spit Harry would still have to follow through with whatever that is for the signal to be sent back in time to cause the urge to drink. Otherwise it would be like Harry escaping from that locked classroom after Draco tortured him without then going back in time and sending the Professor to let him out.
So from what we know of Quirrell, it would be just like him (having recently learned about Comed-Tea) to have a policy of spitting out soda that he drinks, so that no one gains information on whether or not he is surprised.
You are right, those are both possibilities. Though, one of them has been explicitly presented by the author, and endorsed by Harry. I don’t think we have much reason to doubt the canonical interpretation.
“SO THAT’S HOW THE COMED-TEA WORKS! Of course! The spell doesn’t force funny events to happen, it just makes you feel an impulse to drink right before funny things are going to happen anyway! I’m such a fool, I should have realized when I felt the impulse to drink the Comed-Tea before Dumbledore’s second speech, didn’t drink it, and then choked on my own saliva instead—drinking the Comed-Tea doesn’t cause the comedy, the comedy causes you to drink the Comed-Tea! I saw the two events were correlated and assumed the Comed-Tea had to be the cause and the comedy had to be the effect because I thought temporal order restrained causation and causal graphs had to be acyclic BUT IT ALL MAKES SENSE ONCE YOU DRAW THE CAUSAL ARROWS GOING BACKWARDS IN TIME!”
We don’t know that, committing to saying Vldemort is alive conditional on actually giving them a can might suffice.
Harry could still get a false negative. Remember, Harry will feel the impulse to offer a drink to Alice if and only if if Alice is about to be surprised. So not feeling an impulse to offer her a drink would indicate that either that Alice would not be surprised that Voldemort is alive, or that Harry will not actually end up telling her.
Again, we don’t know that. The soda working in two steps as you seem to suggest (detecting future surprise, then determining whether that surprise is sufficient to cause soda spitting when drunk at the right time) is consistent with what we know about the soda. But that’s not the only possibility consistent with what we know. The soda could also work in a single step and detect whether soda drunk at various points would be spit, without directly detecting surprise at all.
Regardless of the reason for the spit Harry would still have to follow through with whatever that is for the signal to be sent back in time to cause the urge to drink. Otherwise it would be like Harry escaping from that locked classroom after Draco tortured him without then going back in time and sending the Professor to let him out.
So from what we know of Quirrell, it would be just like him (having recently learned about Comed-Tea) to have a policy of spitting out soda that he drinks, so that no one gains information on whether or not he is surprised.
You are right, those are both possibilities. Though, one of them has been explicitly presented by the author, and endorsed by Harry. I don’t think we have much reason to doubt the canonical interpretation.