So how come it's suppose to be so unintuitive? I didn't have no trouble figurin out the questions they asked, an I ain't nothin even resemblin a math prodigy...

EDIT: By "they" I meant whoever wrote that page Brent linked to.
Also, I ain't seen what's so counter-intuitive about QM, either. Not that I'm a master o it by any means, an there's likely quite a bit about it that I don't know, but the basic ideas that folk like Brian Greene say are so counterintuitive jes... well, they ain't! They're jes kinda simple an elegant, the same way that the concepts in that link are. Now, I ain't tryin to come across as no kinda prodigy, mind, an I ain't tryin to make myself look good. There's plenty o folk here what could run circles around me in math or QM without so much as breakin a sweat. I jes wanna know why so many folk apparently find these concepts so counterintuitive... Can anybody help me get it?

Well, the whole idea of things being counterintuitive is really rather vague. What it seems to mean is that your intuition rather strongly tells you one thing, but the theory tells you that something entirely different is true. But that can only happen if you have either trained your intuition in the old mode of thinking (as classical physicists had done before QM came along) or are a stubborn cuss with an inborn certainty that whatever you happen to thing is right.

Now most people don't fall into either of these categories, and in my experience as a teacher, people have nearly zero confidence in their intuition about physics or mathematics. These subjects leave most people completely cowed. I don't mean that they are afraid of math or physics exactly, but that they completely abdicate their own point of view whenever math or physics comes along. I continually have to fight with my students to get them to assert anything at all; they are so afraid to be wrong and so sure that the theory is full of "tricks" which will catch them out, that they just passively wait for the truth to be explained.

To people with this attitude, nothing is especially counterintuitive, because they have accepted the false idea that EVERYTHING is counterintuitive in the mathematical sciences, so they shut off their brains. They typically don't have the force of confidence necessary to really pursue high level training in these fields.

At the other end of the spectrum are people who really process new ideas very thoroughly and have no trouble revising their intuition as new information becomes available. They also do not usually feel that things like QM and Bayes' Theorem are strikingly counterintuitive, if they encounter them EARLY ENOUGH in their education.

So who is it that feels these things are strongly counterintuitive, and why do they get so much press? In my opinion, this is coming from professional physicists themselves, parroted by science popularizers who know that if they call a theory "mind blowing" they'll sell more copies.

The root of the problem, I think, lies in how science is taught. Science teaching at the college level usually takes a historical approach, in which the lectures follow the historical development of the subject. Every science has a dividing line, before which it was "old school" and "quaint" and WRONG, and after which it is "new" and "modern" and RIGHT. This dividing line is usually associated with a person, who functions the same way mythological figures do, as a symbolic founder the subject. Just as Finn Mac Cool was the mythological founder of Ireland, Aeneas of Rome, and Abraham of Israel, so Euclid was the founder of mathematics, Darwin of biology, and Newton of physics. (Note: by "mythological," I do not mean non-historical; I'm referring the the psychological impact of these people when I say that they function as mythological figures.)

Everything before the founder is considered prologue, and is not treates quite seriously. Once the founder arrives on the scene, things start moving, the subject grows up and gets serious, it assumes the mantle of Truth. Teachers can't help teaching things this way, because the sciences really have advanced a lot since their beginnings, and some of the early ideas really do look rather misguided in retrospect. Students pick up on these cues, and feel that (in physics for instance) Newton was "the real deal" and everything he said and did was the truth. Again, I'm not talking about a rational assessment of Newton's life and work, which the student is probably not yet equipped to make anyway; I'm talking about the feeling that students get, the feeling that they are learning the Truth. Without specifically intending to do so, most teachers are going well beyond conveying information, and are actually INDOCTRINATING students in the Newtonian world-view.

Now this is not bad and evil; it is an automatic consequence of how people work when they hold a founding figure in reverence; it may even be necessary. After all, it was the Newtonian world view which developed the theories that in turn led to the quantum world view. So perhaps immersing the student in the earlier viewpoint is the only way to walk the student through the reasoning that leads to the new viewpoint. We only have the one timeline of human history to observe, so we can't say whether it is possible to reach the quantum view without passing through the Newtonian view first.

The common (safe) assumption is that we should make each individual pass through the process that occured historically. For a physicst, this means intensive training and (accidental) indoctrination into the Newtonian perspective, until this way of thinking is deeply internalized. Then QM is introduced, forcing a radical departure from that way of thinking. This is where the idea that QM is counterintuitive comes from, in my opinion. Only people whose intuition has first been highly trained and focused on the Newtonian picture have this experience. They they tell everyone else how mind bending it was, and since most everybody else is cowed by physics (and thought it was all EQUALLY bizarre, not just QM), this opinion is accepted; after all, it is the experts' opinion, right? But it's really not their opinion, it's a SYMPTOM of the process by which they became experts, like the dark circles under a grad student's eyes.

Part of the problem is that when people make a mythological figure out of a founder, there can be only ONE. Psychologically, it makes no sense to have two founders 300 years apart, so the first one must be the REAL founder, and his word is law. Then when it turns out that he's wrong, the second founder must be the real one, and the first founder is relegated to the prologue. Once that happens, REAL physics will be considered to have started with QM, and it will no longer be thought counterintuitive. But our historical teaching method prevents this dialectical process from occuring because we continue to train each generation in the Newtonian outlook before springing QM on them.

So there, that's my opinion on why QM is considered counterintuitive. It seems rather strange, looking back at what I've written, that the answer seems to involve depth psychology, history, pedagogical norms, and the historical dialectec. But my opinions are all like that -- a huge mishmash of stuff from god knows where.

--Stuart Anderson