c) As for the cat, thanks Tyro but I still don't get it. I can't say that I understand what I've read about quantum mechanics but I still don't get the cat example
Bad example/parallelism maybe?
It took me quite a while to get the cat thing...I understood it in different terms:
Imagine (instead of the horrifying prospect of dumping poison, uranium, and a live cat into a box and taping it shut
) that you have a simple voting booth. Inside the voting booth is a single switch with which people choose a new victor. One side of the switch says "John" and the other side says "George." In the back of the simple voting machine is a small computer with a single red button which will automatically tally the results and spit out a little piece of paper with the name of the winner when the button is pressed. Now, you're a voting official. Your job is to make sure that people can vote undisturbed and confidentially. At the end of the day, it's also your job to push that button to get the paper with name of the winner. There's no trick to this example...no tampering, no mysterious workings of the computer, just straight-forward voting.
People come in and out all day long and vote for either "John" or "George." As an objective voting official, you keep the peace and certainly do not ask anyone who they are voting for when they enter the booth nor do you ask them who they voted for when they leave. Your day ends and it's time to push that button and tell the reporter next to you who won the election. You head to the little computer and push the red button. Out comes the slip of paper...but oh snap! In your haste to get things ready for the day's election you forgot to check the ink cartridge inside of the machine! The paper containing the name of the official winner is blank!
Schroedinger's poor abused cat is in the same situation as this election. Now, the election result does not depend upon a quantum event like the cat. However, like Schroedinger's cat, the election result does depend on a statistical result, which, in this case, is the number of votes for "John" weighed against the number of votes for "George." Schroedinger's cat, inside of the box, has a 50% chance of being alive. In this election, both "John" and "George" have a 50% chance of being the winner (i.e., there were only two possible outcomes). Now, that reporter that was standing next to you is demanding the result. He says that his readers must
know immediately who won! You know someone won...after all, the computer did it's job...you just don't know who won...as the sheet is devoid of ink. That's Schroedinger's rub...someone actually did
win this election, some people actually voted for "John," some for "George." However, because of the statistical uncertainty (that 50/50 chance for either candidate) you have no idea. Technically, election day is over. People did vote...people did choose...votes were tallied. Only the election is in bizarre state of uncertainty and not because anything out-of-the-ordinary happened during the election. It is because the election results hinged on a statistical result which, all things being equal, gave each of the two candidates a 50% chance of winning.
As the vitality of Schroedinger's cat is unknown until we open the box, so too will remain uncertain the results of our election, at least until we pop in a new ink cartridge and finally find out who's the better backup singer for the Beatles.
Quantum mechanics offer the same sort of statistical uncertainties. We don't know if an electron is here or there but we know it is one of the two places. We could guess it's here, but by the time we look to be certain it's over there, or worse yet, our looking has bumped it over to there. Then, we look over there to see it, but it's now it's moved back to here. It's too small and too fast to grab on to to check, so we're forever guessing. Wild, huh?
Hope this helps,