Up here at the macro level, common sense tells us that a thing is unique and it is in only one place at a time. But in the quantum world a thing is both a particle and a wave and it's in more than one place at once - at least until it is "observed."
The term "superposition" describes the condition where a range of states are true all at once in the quantum world. In Schrodinger's scenario, the cat status is a "superposition" - it is both alive and dead - but when you look, the cat is either alive or dead.
The example I drew earlier is even more extreme, where if you measure the particle's partners both here and on Jupiter at the same time - a paradox exists because the measurement itself instantaneously determines the partner as well. So both statements can't be true. This example was raised in one of Penrose's books.
IMHO, to understand the quantum world it is helpful to lay aside one's concept of physical "reality" --- the same approach is helpful in understanding space/time and higher dimensions.
Just my two cents...
That's not really a good description. The measurement on one of a pair of entangled particles tells you what a measurement on the other pair would give. It does not force that measurement to be made. The tricky part is that this is true for all measurements.
Up here at the macro level, common sense tells us that a thing is unique and it is in only one place at a time. But in the quantum world a thing is both a particle and a wave and it's in more than one place at once - at least until it is "observed."
There is no objection to the principles of quantum mechanics or the use of terms like particle, or wave, or even color and strangeness, to provide a way conceiving the mathematical results of observed phenomena. The mistake that is made, not so much by scientists, but by those who accept their language as descriptive of events in the macro-world, is that if it were true, it would invalidate the source of the experimental data the theories are based on.
For example, it would have to be concluded that every meter reading had no particular value until someone read it and whatever value something had where the experiment is being made would actually be repeated someplace else. If the world really acted that way, someone would notice, I think.
In the case of Schroedinger's cat, suppose no one bothered to look for a month. (We are supposing the cat is nourished in some way.) That would mean it could not die, if it died, until someone looked, else the cat might have been dead for two weeks, and quantum uncertainty will not prevent biological decay or stop time.
It was mistakenly called a thought experiment.
Consider this. The following have never been observed: force, field, and electromagnetic waves.
There are endless experiments that demonstrate such things, but the things themselves are never observed. From the experiment using iron filings and a magnet to demonstrate a magnetic field, to the double-slit experiments to show the interference of light, all that is observed are the results of the experiments. The actual phenomena they are meant to illustrate or study are interpretations of what is observed.
The concept "force" is universally accepted as a concept for something, an actual existent, but in fact, all that has ever been observed is acceleration. We can actually observe acceleration, (a second level integration, if you're a calculus fan), and we can attribute the concept force to that, which makes our formulas convenient, and it fits with what we physically "feel" in the presence of acceleration. But force, itself, has never been seen or observed in any way.
Force is certainly a valid concept in science, and useful for the description of many phenomena, and as a name to which we can attach values in our mathematical values. A rally good scientist that understands the nature of the concepts, knows force is not ontologically real, it is only real as a concept for how material entities behave (they really do behave that way). We notice that two bodies of a certain mass accelerate toward each other. The rate of acceleration is all that can be observed. We know that bodies with mass behave this way. The name we give to the general principle of observed behavior in the relationship between bodies with mass is "force."
Most of advance science deals with observed behavior and creates useful concepts to name and give values to that observed behavior. Very few, if any of those "things" are ontologically real. They are all real, in terms of being valid observations of behavior. They are not real, if by that one means, they have independent physical existence from those macro-world entities of which they are only descriptive.
The mistake that science has made is in using its conclusion to assert that the world as pictured by scientists is the real world, of which the world of every day is only an appearance or even illusion. It is a mistake, because all that science studies begins with this every day world. If it is invalidated as an illusion by science, the very thing science studies and the basis for all its conclusions is invalidated. Science, in that case ceases to explain, and only explains away, and what it ultimately explains away is itself.
[I have posted this because both of you give a great deal of credence to science, and rightly so. You also seem to hold reservations about the legitimacy of science to deal with certain aspects of knowledge, with which I agree, but for different reasons. I think science is unable to provide answers to questions of a purely philosophical nature because its sole purpose is to study the nature of, "dead matter," so to speak. I regard questions of metaphysics, life, volition, values, aesthetics and so on, matters which lie outside the field of the physical sciences but within the province of philosophy. This, I think, is our major difference. While you entertain doubts about science, you still rely on it to provide insights into areas I think it is incapable (and ought not try) to deal with.]
Hank