patrick.net

The cat was just a thought experiment to illustrate quantum entanglement.

Too many people try to apply this to our real world and make sense of it when they should not.

That damn cat is dead, I opened the box and force-fed it the cyanide.

IT's useful in this case for spelling out a simple logical fact to some who otherwise for whatever reason might not be able grasp it.

You're thinking of the Heisenberg uncertainty principle and specifically the concept that the observer affects the observed. While it's true in some ways maybe, that is what people are talking about when they say QM inferences about particle physics don't apply at our gross level.

MY example here is just a very simple easy to understand point about logic, and the aliveness of the cat, and was meant to be 100% independent of any connection to particle physics.

Haha, good luck with that. 99% of humanity is perfectly comfortable with a head full of paradoxes. They don't care to reconcile anything as long as most of it gets them through the day alive.

MAybe I should have stuck to the thread. In another thread Dan said.

Dan8267 says

First, one does not need to prove something that cannot be disproven by definition. Anything that cannot be disproven by definition is false.

Worded awkwardly, but I'm pretty sure he is using some fallacious reasoning that I attempt to dispel above in as simple and clear a way as possible.

Meanwhile, you're right.

http://www.HCOE__N6v4o

I don't even own a cat!

Ah, Schrödinger's Cat, the most misinterpreted experiment, thought or otherwise, in the history of the world. This is quite ironic since Erwin Schrödinger made up this experiment to demonstrate how confusing and misleading some fancier interpretations of quantum mechanics are. Schrödinger's concern was that the general public would misinterpret quantum mechanics to be some kind of voodoo magic, and then the general public completely misinterpreted his thought experiment.

All right, I will try to clarify this subject matter. First off, mechanics is the study of basic physical properties like energy, mass, and how bodies behave when subjected to forces. Mechanics includes studying things like tools (levers, pulleys), friction, and acceleration of bodies including orbits. Quantum mechanics studies similar things as they apply to the very small in size and mass, for example, atoms, protons, electrons, etc.

Ok, now imagine that for a course in mechanics you wanted to measure the temperature of a bucket of ice water. Now, of course, we all know that the temperature of a bucket of ice water at atmospheric pressure is, by definition, 0 degrees Celsius. So we expect our thermometer to read zero when we take the temperature.

But let's say the thermometer we use is an industrial strength thermometer designed to measure the temperature of molten iron. We take the thermometer out of a vat of molten iron and stick it into our small bucket of ice water. Immediately, the water begins to steam and the ice melts and evaporates. We're left with a partially melted bucked containing no water or ice by the time the thermometer settles on a temperature. We read the temperature as 200 degrees Celsius and conclude that an ice water mixture has that temperature. Good science, right?

Well, no. You see, we fucked up. We forgot that "for every action, there is an equal and opposite reaction" and what that means. Well, for one thing, it means that any thermometer we use, any at all, will itself have a temperature and some heat. Normally, we can easily discard the effect on temperature that the thermometer will have on what it's measuring the temperature of. We can normally discard this effect because it is utterly insignificant.

However, in our faulty experiment, we took a thermometer whose temperature and heat content were "big" relative to the temperature and heat content of the thing it was measuring. As a result, the temperature had a comically large effect on the object it was trying to measure a property of. Of course, common sense would keep us from doing something so ridiculous in the real world.

So, what does this have to do with quantum mechanics? Well, everything in quantum mechanics is small, damn small. In fact, quantum mechanics deals with the very smallest things in the universe. That's kind of the whole point of quantum mechanics. And since we're dealing with the very smallest objects in the universe, any thermometer we use will be "big" relative to the thing it's measuring.

And wait, that's not all. It's not just thermometers that cause a problem. Any device at all which measures any physical property (location, speed, electric potential, mass, anything) will have a significant effect on that object. We can't even measure the kinetic energy of an electron without significantly affecting the electron.

Fortunately, there is a simple equation that describes how much error our attempts to measure something will introduce. It's called the Heisenberg Uncertainty Principle and it calculates a maximum error in the same way that your calculator uses Taylor Series Approximations to calculate sins and cosines and the upper limit on the error of these approximations. Ah, brings me back to high school calculus.

So the practical side is that in quantum mechanics, you can indeed make the same kinds of measurements that you do in macro-mechanics -- you know, high school physics -- except that in quantum mechanics you have to keep track of the upper limit of error (or uncertainty) in all your calculations because this uncertainty is significant since you're dealing with really small things.

Well, that doesn't sound too bad. It's pretty pedestrian. Hardly seems relevant to the discussion of god or anything mythical. It sounds down right mundane. Enter the people with overactive imaginations…

One of the practical consequences of the uncertainty of quantum mechanics is that you don't know when some particular unstable atom is going to fission itself into a more stable configuration by performing radioactive decay. This is why we talk about the half-life of various isotopes of elements. We don't know when each particular atom is going to decay, but we know that statistically and predictably half of the atoms in a sample will decay in time T. So we call that time the half-life.

Now we're getting close to Schrödinger's thought experiment, so bear with me -- or, if you prefer, bare with me, I won't mind.

First, let me clarify that The Theory of Quantum Mechanics is a very successful theory that has with great precision been verified. It is both a theory and a fact just like evolution and gravity. Theory does not mean "guess". Quantum Mechanics has also proven to be extremely useful in practical matters such as computing, encryption, fuel efficiency, etc. It is a well-established theory that has already bore much economic fruit.

That said, we are dealing with the forefront of scientific understanding. And at that forefront is always brain-storming, imagination, and conjectures. There is nothing wrong with that as long as you can distinguish between "what might be allowed by our theory" and "what we know to be true according to the theory". These are two entirely different things. For example, Einstein's Theory of Relativity predicted black holes and we now know these to exist. Relativity also allows, in that it doesn't out-right prevent the existence of, wormholes. Now wormholes might exist, or they might not. Maybe we'll even expand Relativity to the point where we either prove the necessity of wormholes or the impossibility of wormholes, but that hasn't happened yet. Wormholes are just a conjecture, not something we know for sure exists.

Having clarified that, I will let you know what led Schrödinger to come up with his experiment. Yes, it all ties together.

A very bright and successful physicist, Niels Bohr, was dealing with the troubles that uncertainty introduces in physics -- yes, I'm dumbing this down, but I'll link to a more detail discussion. To deal with these problems, Bohr developed the Copenhagen Interpretation of Quantum Mechanics which is a kind of paradigm for dealing with the counter-intuitive world of quantum mechanics -- quantum mechanics is counter-intuitive because our intuition evolved to deal with problems on our scale and not the scale of the very small. The link above goes into more detail, but the important idea to understand for this discussion is that the Copenhagen Interpretation is not the Theory of Quantum Mechanics, but rather a mindset used to deal with quantum mechanics.

Side Note. Copenhagen is not the name of some long dead physicist. Copenhagen is the capital of Denmark and a city in which a lot of physics including the early works on quantum mechanics took place. In fact, the Niels Bohr's Institute for Theoretical Physics is located at the University of Copenhagen.

So, once again I need to simply things as much as I can without distorting their meanings. One of the most direct consequences of the Copenhagen Interpretation is the philosophical principle that a property of an object (say velocity) has every possible value until it is observed. This is different from the Uncertainty Principle which only says we cannot measure properties without affecting them and other properties and thus introducing an error or uncertainty.

Some people, including Schrödinger, had objections to this philosophical interpretation of a physical theory. So Schrödinger devised the following thought experiment to demonstrate the "silliness" of the Copenhagen Interpretation. The Schrödinger Cat experiment is actually a standard argument form (I forget the name) in which you get the proposer of an idea to reject a necessary (even if extreme) consequence of the idea and in doing so discredit the idea. As readers know, I do this all the time.

Schrödinger's Cat Thought Experiment (kids, don't try this at home)
1. Get a box, a cat, some poison, a hammer, a radiation detector, some scrap electronics, and one radioactive atom.
2. Put the cat in the box with a vial of poison and the radioactive atom.
3. Set up the sensor to detect the radioactive decay of the atom and to use the hammer to break the vial when the decay happens. The poison will be released and the cat will die.

The whole purpose of this experiment is to reject the Copenhagen Interpretation by showing that its consequences are ridiculous. Unfortunately, the Copenhagen Interpretation deals with quantum mechanics and everything in quantum mechanics is ridiculous -- true, yes, but ridiculous nonetheless. So, Schrödinger had the brilliant idea to transform the quantum uncertainty into macro-uncertainty.

Remember, that the Uncertainty Principle says that we can't know when or even if the particular unstable atom in our box will decay. The Copenhagen Interpretation says that means the atom is both in a decayed and not decayed state (the only two possible states in our case) until it is observed. Well, as long as we keep the box closed, we're not observing anything. But if the atom is both decayed and not, then the sensor has both gone off and not have gone off. So the poison has both been released and has not been released. So the cat is both dead and alive, but not in the good zombie way.

Well, no one is going to accept that the cat is both alive and dead until we open the box and then it spontaneously and randomly assumes one and only one of those two states. So clearly the Copenhagen Interpretation is wrong.

But wait, the advocates of the Copenhagen Interpretation rebut. The interpretation merely says the event must be observed, not necessarily by humans. So, the cat is either dead or alive because the non-sentient sensor observed the event. No problem. You can't trigger the poison to be released without observing the event and that collapses the wave function -- I'm dumbing things down, but that's the basic point they make.

Fair enough, but everything is always being observed if you include every non-sentient particle in the universe. You are constantly reacting with photons, electrons, and atoms. So if our sensor is enough to render the Copenhagen Interpretation impotent, then wouldn't the mere presence of all the stuff in the universe in effect always render the Copenhagen Interpretation mute?

Put simply, the idea that uncertainly means that a property takes on all possible values simultaneously is utterly meaningless if you also add that once that property has any effect on the universe it is no longer "all possible values" but some particular value. What have you really added to the understanding of quantum mechanics? What phenomenon are you explaining? What would be the difference between a universe in which the Copenhagen Interpretation operated and one in which it didn't? The answer: nothing.

I hope this explains the Schrödinger's Cat experiment and why that thought experiment does not mean "a god that is undefinable might exist" or "a statement that is unprovable by design can be true". What the Schrödinger's Cat experiment demonstrates is that just because we don't know what the value of a property is, doesn't mean the property takes on all possible values. And please, don’t misinterpret the experiment as so many do as believing that the cat really is both dead and alive. That is not the right answer.

Dan8267 says

And please, don’t misinterpret the experiment as so many do as believing that the cat really is both dead and alive. That is not the right answer.

Gawlleee Dan, your smart. Nice job trying to obfuscate my point.

I said very explicitly my point had nothing to do with particle physics.

Even here when I make a point about logic that any smart 10 year old can understand, Dan doesn't even try to understand my incredibly simple point. Instead, he launches in to an effort to show us all how smart he is.

Here:

You are right. If we take the fact that we can not know whether there is a God as an axiom,

Then the statement God exists is false.

My point:

The statement God does not exist is equally false.

My apologies if I didn't make that clear enough. Also my apologies for thinking that this simple and elegant thought experiment might be used to illustrate a logical point outside of the quantum mechanics context it's known for. I'm such a fool sometimes.

I will admit his response was predictable, but not what I was hoping for. Next prediction: My New "Enlightened Atheist" Thread which is meant to be appreciated in it's entirety will be broken apart in a statement by statement, phrase by phrase, Shrek like manner, probably before he even reads the whole thing.