The behavior of particles

Hello everyone!

I have been until recently away from this beloved DV community for some time. I've returned a very changed person, and I am now ready to participate in the scientific pursuit of knowledge. I am in this, and in many other ways, new to this concept. I vow to approach everything with a mindset of "perhaps" instead of a mindset of "this is certain." With that, I beg the patience and forgiveness of those who actually know what they are talking about. I come to you only with ideas, and "what ifs" and I don't intend for them to seem in any way "certain."

I have spent quite some time delving into theoretical physics and quantum mechanics. I am... horrid at calculus, and thus I fear that I am incapable of exploring further the areas of science which so fascinate me. I hope that those of you who are learned and experienced in these subjects can share your knowledge with me, and new learners like me!

I have recently been pondering the behavior of particles. To get straight to it, as most of you are probably aware, generally speaking, particles often behave differently than we expect them to on the quantum level. Electrons forming interference patterns in the double-slit experiment, yada yada yada. We have also seen that the mere observation of the behavior of particles seems to always interfere with the behavior of the particles! Upon observing the otherwise seemingly unpredictable particle behavior, they appear to behave how they would expect them to- in accordance with laws of classical physics (on the macroscopic level.)

I wonder then, like many others have probably wondered- does the observed behavior of particles change to fit laws of classical physics because that behavior is actually what should be happening, or would that behavior reflect our expectations even if those expectations were not consistent with classical physics?


To simplify, if we once again perform the double-slit experiment, but we [somehow] force ourselves to expect something which is otherwise scientifically impossible, would the particles behave in that way?

I hope my question is clear. Basically, does the particle's behavior change to be consistent with macroscopic physics because we expect it to, or because macroscopic physics is actually universally true, even on a quantum level? I am leaning towards the former- the particles behavior changes to fit what we expect to see. SO- if we were able to convince ourselves to expect a completely impossible third outcome.... would the particle behave in that way?


I hope I am making sense. Thanks for reading.

Rainman


ADDENDUM- if particle behavior is impacted by observation, why were we able observe electrons making quantum leaps before we knew that such a thing were possible? All of quantum physics seem to indicate what would be perceived as impossibilities on the macroscopic level is actually possible. They seem to happen regardless of the presence of a conscious observer. Does this invalidate the findings (or lack thereof) of the double-slit experiment?

At very first I thought you were Xei, but then I realized. Welcome back Ninja.

I understand your question by the way, and I can only answer with a resounding "I don't know." Why? Because I haven't thought of the next way I could expect a particle to behave. It's clear already that the notion that a superstate or superposition of sorts exists in which the entirety of the universe is contained in all its fragments and can call upon themselves willingly to manifest themselves in a way that results in a one final outcome. What it is it? Exactly what you expect it to be.

If the universe is created by consciousness, then expectation might conceivably be the laws of physics. On the other hand, maybe the laws of physics are fixed, in which case expectation probably matters little.

Unfortunately, of course, no one knows which of these two ideas is the right one (if any of them is).

One argument in favour of the expectation-as-the-laws-of-physics idea is that historically observations have led to the formation of theories, and the subsequent experimental evidence has tended to confirm the theories for a long time. Then divergence appears, and in response new theories are formed. And then the wheel turns once more. This system has been going since the ancient greeks, and until this day.

It would seem that we tend to get what we expect, for a long time, and then we don't, for a short while, and then we go back to getting the expected again.

I don't really know what you mean by... particles act classically when we observe them. Particles act according to the laws of quantum mechanics, all the time. These are simply... the laws of the universe. There is no "classical version" of them which kicks in when we're looking. Classical physics just falls out of the equations of quantum physics on large scales. For instance... the "orbit" of an electron around a nucleus is explained by quantum physics. The fact that energy is a discrete quantity is what stops the electron from losing energy and spiralling into the nucleus. When you're "observing" an atom, the electrons don't all suddenly start spiralling into the nucleus.

I think you're over-complicating things. Probably you've been given a misleading presentation of the subject by a non-scientific source. Quantum mechanics is just how the universe works. Our expectations are irrelevant.

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Originally Posted by Denziloe

Quantum mechanics is just how the universe works. Our expectations are irrelevant.

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That's exactly what they used to say about classical physics ...

That's still true. Classical physics is still an excellent model of the domain of observations which it concerns. It was and still does make extremely accurate predictions. No new observations will somehow make that false.

Quantum mechanics simply explained new sets of observations (viz. the microscopic world) which classical physics did not observe and thus, unsurprisingly, did not make correct predictions for. Quantum mechanics is also an extremely accurate theory for all the observations which it is designed to model and no new observations will somehow make that false.

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Originally Posted by Denziloe

That's still true. Classical physics is still an excellent model of the domain of observations which it concerns. It was and still does make extremely accurate predictions. No new observations will somehow make that false.

Quantum mechanics simply explained new sets of observations (viz. the microscopic world) which classical physics did not observe and thus, unsurprisingly, did not make correct predictions for. Quantum mechanics is also an extremely accurate theory for all the observations which it is designed to model and no new observations will somehow make that false.

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The point being that classical physics doesn't provide an accurate unified model. Yes, it's accurate on a relatively large spectrum, but too far on any end of the spectrum and it breaks down. You are agreeing with what both of them are saying but telling them they are wrong by making the distinction in the first place. Newton's theory of gravity provides an accurate model for us to follow but does not account for many of the things covered in either of Einstein's theories of relativity. Does it provide an accurate way with which to model a great part of what we can observe? Of course, but when you apply it to other areas it isn't as accurate because it is far simpler. I mean, an extremely important distinction here is discovering that gravity only seems like a force rather than actually "being" one per se. Can you see why now that it's important to differentiate between things here? You can claim up and down that it isn't, but then why do you do it in the first place then?

Thanks for your replies, everyone.

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Originally Posted by snoop

At very first I thought you were Xei, but then I realized. Welcome back Ninja.

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I don't know if that's meant to be sarcasm, but I have been a member here since 2007. Perhaps you forgot to look to your right, below my photograph where it clearly says "Join Date: May 2007." While both Xei and Ninja were active, I had regular, long, ongoing arguments with the both of them. I assure you, I am not any former banned member, I have been Rainman for seven years, and most of the oldies know who I am, I'm surprised you don't remember. But uh, thanks I guess.

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Originally Posted by Voldmer

If the universe is created by consciousness, then expectation might conceivably be the laws of physics.

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This is what I have been pondering, and kind of what I'm getting at in this post; it's quite far-fetched, but I believe relativity was far-fetched when it was hypothesized as well. I think this could be a possibility. I believe that if observation changes the behavior of particles (I believe that it does, and there's good reason to believe that it does) then that could mean there are some very big connections between what we experience and what we expect.

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Originally Posted by Denziloe

There is no "classical version" of them which kicks in when we're looking

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Apologies, this is untrue, and has been demonstrated hundreds of times using photons, electrons and even molecules. According to classical physics, if many particles travel through two slits and their destination can indicated where they land, they should form two groups resembling the slits they traveled through. What actually happens is that they behave like waves. This is already well-known. However, when we observe individual particles in this process, we witness them behaving the way particles "should" according to, yes, classical physics which yes, is a thing. This suggests that either the particles randomly behave in one way or the other (they don't) or that they behave like both simultaneously, which still contradicts, yes, classical physics which yes, is a thing. Niels Bohr went as far as to state that the act of observing the particles caused them to behave the way we would expect them to AS PARTICLES. Einstein disagreed vehemently, stating that he would "prefer to think that the moon is there, even when he's not looking at it."

So much of quantum physics relies on an observer. I think we should start considering observation as a variable in experiments. There should be more studies on the matter of *IF* observation actually does impact behaviors of particles, and if so, does the observation impact particles in a consistent way? Is there a way to recreate the outcomes of observation in a reproducible specific way that we can alter?

Welp, sorry about that. Wouldn't be the first time I was wrong. Don't typically look at member's join dates, maybe it's about that time, eh?

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Originally Posted by Rainman

This is what I have been pondering, and kind of what I'm getting at in this post

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I realised that, and only stated it here directly in order to make my own post self-contained.

And the idea is compelling. After all, physical reality could trivially be produced by consciousness, since it already produces life-like dreams. However, the other way around is much more difficult to understand. Up until now there is no clearly correct theory of how matter should be able to produce consciousness.

This also makes you wonder, why the "standard" assumption for so many people is that "physical reality" is all there is.

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Originally Posted by Rainman

Apologies, this is untrue, and has been demonstrated hundreds of times using photons, electrons and even molecules. According to classical physics, if many particles travel through two slits and their destination can indicated where they land, they should form two groups resembling the slits they traveled through. What actually happens is that they behave like waves. This is already well-known. However, when we observe individual particles in this process, we witness them behaving the way particles "should" according to, yes, classical physics which yes, is a thing. This suggests that either the particles randomly behave in one way or the other (they don't) or that they behave like both simultaneously, which still contradicts, yes, classical physics which yes, is a thing.

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You kinda just... ignored my counterexample.

What do you mean by "acting classically"? Particles always act according to the laws of quantum physics. Whenever we take a measurement of a quantum wave, it collapses to a point. This is what happens in the double-slit experiment. That's very weird behaviour. I don't know of any classical phenomenon like that. When the particle collapses, it continues to evolve according to the laws of quantum physics. At no point does it start acting like a classical billiard ball or something. If you'll allow me to speculate on your meaning on your behalf, it sounds to me like you're saying that points are inherently "classicalish" as opposed to waves which inherently "quantumish". But that is not the case; waves are a fundamental classical phenomenon. Or perhaps you're saying that deterministic behaviour is inherently classicalish - but at no point do particles act deterministically.

And to return to my counterexample - the double slit experiment is not the only empirical result in all of quantum mechanics. There are of course many other interesting quantum phenomena. One of the most basic is that physics is in some sense discrete. Energy, for instance, is discrete. Particles can only ever have a whole multiple of a basic quantity of energy, rather than being allowed any quantity of energy as in classical mechanics. This does not become false when the particles are observed. As far as I can tell this answers your original question - with a "no". So if you don't think this is the case, I would be appreciative if you could tell me what you think about this in your next response, so that I can understand better what you are saying.

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Niels Bohr went as far as to state that the act of observing the particles caused them to behave the way we would expect them to AS PARTICLES. Einstein disagreed vehemently, stating that he would "prefer to think that the moon is there, even when he's not looking at it."

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Bohr's original quote and its context would be appreciated.

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So much of quantum physics relies on an observer. I think we should start considering observation as a variable in experiments. There should be more studies on the matter of *IF* observation actually does impact behaviors of particles, and if so, does the observation impact particles in a consistent way? Is there a way to recreate the outcomes of observation in a reproducible specific way that we can alter?

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Observation is already an integral part of quantum theory. And quantum theory already provides an excellent model of all of the experiments you're talking about, so pretty much by the whole definition of a scientific model, it doesn't need modification.

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Originally Posted by snoop

The point being that classical physics doesn't provide an accurate unified model. Yes, it's accurate on a relatively large spectrum, but too far on any end of the spectrum and it breaks down. You are agreeing with what both of them are saying but telling them they are wrong by making the distinction in the first place.

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I don't follow. This thread isn't about unified models and nor was my response. The original question was raised entirely on the basis of the double slit experiment, which is a prototypical result of quantum theory and does not raise any problems in that theory which would require some kind of theory of everything. Voldmer's response was therefore not relevant to my reply. What he is implying - that quantum mechanics does not have universal scope - is true, and actually already known to be true, but that has nothing to do with the original question that was raised or my reply to it. And as to your assertion that I am agreeing with the contention of the original post - I'm not sure what to say to that, because I am clearly not. I kindly ask that you read my follow up response in this post to get a better idea of what I'm saying.

The problem with your position, as I see it, is this:

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Originally Posted by Denziloe

Quantum mechanics is just how the universe works. Our expectations are irrelevant.

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It has never been proven that Quantum mechanics (QM) is how the universe works, and indeed there are countless examples of incidents that quantum mechanics could not predict. Your statement to the effect that QM rules the world is therefore a statement of faith - not of knowledge. There is, of course, nothing wrong with having faith. But those who do not share the same faith will obviously consider a wider field of possibilities - including the possibility of expectation ruling the world.

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Originally Posted by Denziloe

Voldmer's response was therefore not relevant to my reply. What he is implying - that quantum mechanics does not have universal scope - is true

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I actually implied that quantum mechanics might be fundamentally wrong - just as classical physics turned out to be.

Sorry, Denziloe, I didn't notice your counterexample the first time through.

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Originally Posted by Denziloe

The fact that energy is a discrete quantity is what stops the electron from losing energy and spiralling into the nucleus. When you're "observing" an atom, the electrons don't all suddenly start spiralling into the nucleus.

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The fact that energy is a discrete quantity is what stops the electron from losing energy and spiralling into the nucleus. When you're "observing" an atom, the electrons don't all suddenly start spiralling into the nucleus.[/quote]

I have no valid counterargument to this. It is a perfectly valid point, and I don't understand classical nor quantum physics yet well enough to contest it. Perhaps someone else here can, or perhaps your argument is not contestable using my logic.

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Originally Posted by Denziloe

What do you mean by "acting classically"? Particles always act according to the laws of quantum physics.

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I mean that things don't behave the way they "should" according to CLASSICAL PHYSICS! You keep repeating this as if I'm saying something outlandish or unreasonable. I understand what you're saying! I understand that the universe always has and always will operate according to quantum physics! But until recently, we didn't know that. We thought it behaved according to classical physics, our original understanding of physics. The problem is that as much as we have learned, we ultimately know little about quantum physics. We utilize it in many ways through technology, yes, but quantum physics is not taught in school. It's not the common understanding of how things work, outside of those who work or research in that subject.

According to the laws of quantum physics, technically, I can't be completely sure that I am definitely sitting exactly where I am sitting right now, and I can't be sure when "now" really is. But I've always been taught to believe that matter is definitely where it is and that time is universal (rather, I was not taught that light is not relative and that time is.) Obviously that's an exaggerated example, but I think you can understand my point. The quantum physics community is the only community that actively accepts (for non-spiritualist reasons) occurrences of "spooky action" or that entangled electrons means that from a theoretical standpoint, teleportation of molecules could be possible, or that if I were able to live aboard a fighter jet traveling at the speed of sound perpetually, I would age more "slowly than" you.

A lot of what seems like common sense to people who study this subject is still seen as science fiction by most people; and that is true because classical physics is what is still taught, and not quantum physics. The unfortunate mislabeling of complete spiritualist garbage as "quantum" this or that has also contributed to general confusion about what it is, which is infuriating.

That is what I am saying. When I say "behaving classically" I am in effect saying "according to our classical understanding of physics" which is obviously no-longer valid. But it's apparently only no longer valid in this context, because it is still what's taught in schools. I was taught that particles behave one way, and quantum physics has totally made me scratch my head and say "what the hell?" So, because I do not yet understand quantum mechanics on a level that you and others probably do, I am just asking questions.

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Originally Posted by Denziloe

Bohr's original quote and its context would be appreciated.

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I will try to find the bit about Niels Bohr's belief about observation. It was in a PBS documentary about quantum mechanics.

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Originally Posted by Denziloe

And to return to my counterexample - the double slit experiment is not the only empirical result in all of quantum mechanics. There are of course many other interesting quantum phenomena. One of the most basic is that physics is in some sense discrete. Energy, for instance, is discrete. Particles can only ever have a whole multiple of a basic quantity of energy, rather than being allowed any quantity of energy as in classical mechanics. This does not become false when the particles are observed. As far as I can tell this answers your original question - with a "no". So if you don't think this is the case, I would be appreciative if you could tell me what you think about this in your next response, so that I can understand better what you are saying.

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I was about to type a wordy response to this, but then I read:

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Originally Posted by Denziloe

Or perhaps you're saying that deterministic behaviour is inherently classicalish - but at no point do particles act deterministically.

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If I understand you correctly, then I think you've solved my question. I am saying the fact that we classically would not have expected particles to behave like waves, and the fact that they do, is (or at least was when it was realized) confounding. The fact that they at least appear to revert to behaving the way we expect them to once they are observed, is interesting, and is the basis for my question, which is based on Bohr's postulate (I promise, I'll look for it and post a link when I find it); does our expectation and/or observation impact their behavior?

As you mentioned, in many other experiments, particles don't behave according to classical physics when observed. Granted, this is completely valid. But it only has to happen once, right? It happens a lot (as in, repeated in that one experiment that I am aware of lol.) I'm very sorry that I keep referencing the double-slit experiment. It just seems much more clear to me than the few others I've read in-depth about. I'm sorry I can't contribute more to the discussion. These are just ideas.

The effect of observation also applied to electron entanglement according to Bohr (in fact, this may have been the issue he was discussing in the first place.) I don't really understand entanglement, so I can't argue my question in that context, but I do know that its been brought up in conversations about entanglement and why it works before. Our only current explanation is literally "spooky action." We don't know how a lot of this works, Denziloe, we just know that it does indeed work. That's all I'm saying. Thanks for your insight and patience with a quantum newbie. You've helped answer some of my questions.

On a side note, everyone sucks at calculus. It is like trying to learn a new language. I wouldn't give up just because you suck at it, it just takes more practice and eventually it all starts coming together.

Haha. Thanks Alric. I am fantastic at learning languages, but absolutely dreadfully unskilled at calculus!

Like Denziloe, I see the source of the OP's confusion in a muddle-up about classical and quantum-physics supposedly changing from one to the other upon observation and I guess, that's dealt with already.

Just at the side, I'm forty, unfortunately, but fortunately, I did indeed already learn about QM in school. That it's there, what it describes, how it doesn't really go with RT, and a general overview. Oh - and I used to try myself at calculus in advanced math class, too - completely forgotten by now, except that is wasn't exactly easy, but doable.

That wouldn't be the next step in getting a bit better acquainted with modern physics, though, Rainman, rather get a good, professional book - written for laypeople. Like Short History of Time by Hawkins, not sure that has QM, though, but this one has:
A Short History of Nearly Everything - Wikipedia, the free encyclopedia
It's challenging and taxing enough to read such books, I have the Hawkins one with pictures, that's very recommendable, but it took me a long time to take it in, and I didn't understand everything either, and by now forgot the most of it.
If you are really interested - that's the way to go - not calculus, surely not for first tentative steps and seeing, if it's interesting you enough to put in the mental work. :wink:

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Originally Posted by Voldmer

One argument in favour of the expectation-as-the-laws-of-physics idea is that historically observations have led to the formation of theories, and the subsequent experimental evidence has tended to confirm the theories for a long time. Then divergence appears, and in response new theories are formed. And then the wheel turns once more. This system has been going since the ancient greeks, and until this day.

It would seem that we tend to get what we expect, for a long time, and then we don't, for a short while, and then we go back to getting the expected again.

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Concerning how Einstein's Theory came to it's first application - a snippet from Wikipedia:

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At its introduction in 1915, the general theory of relativity did not have a solid empirical foundation. It was known that it correctly accounted for the "anomalous" precession of the perihelion of Mercury and on philosophical grounds it was considered satisfying that it was able to unify Newton's law of universal gravitation with special relativity.

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As far as I understand that, and remember it, too - first came the observation of the unusual orbit of Mercury, and then came the formulation of Relativity Theory by Einstein to provide explanation for it, since Newton's failed in that respect.
In so far, it was like you described it in your first paragraph,Voldmer, and QM, as far as I know, also sprung from observations of it's effects, followed by formulation, and solidified by it's predictive power and consistency.

But your second paragraph sounds as if we would have already looked at something and gotten the expected results, and then suddenly weird effects show up, which were not there before. That's not the case, though - where we find "weirdness" - we haven't properly looked before.
It seems as if you claim the universe would have given us, what we expected for a long time, say in the double-slit experiment, and then suddenly one day, we look again and need a new theory.
Maybe I misunderstand you, but it's neither historically the case, nor would it make conceivable sense. In fact - if the laws of physics suddenly changed in completely capricious ways - I would seriously start to consider, if we might not be inhabiting a simulation.

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Originally Posted by StephL

Maybe I misunderstand you, but it's neither historically the case, nor would it make conceivable sense. In fact - if the laws of physics suddenly changed in completely capricious ways - I would seriously start to consider, if we might not be inhabiting a simulation.

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Maybe I didn't state it quite directly enough, but I wasn't suggesting that observations suddenly became erratic. What I meant was that as we started to look more carefully, it turned out that the existing theories didn't quite get the details right. And that encouraged deeper study, and taking a fresh look at the problems, which eventually led to new theories.

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Originally Posted by Denziloe

Quantum mechanics is just how the universe works.

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Well not really. It's how we see the universe working.

This is a major contention with me and the way people view science. People view science as "the truth". But science is more "a validated view of how we see things work". Quantum mechanics is our mathematical model of particle physics.

In fact quantum mechanics is based on probability, so it's not "how the universe works", it's limited by what we can do.

This is what bothers me when people say something can't exist because science hasn't proven it. First, science isn't reality, it's a transcript of OUR perception of reality. We're limited by our perceptions to truly know what reality actually is. For all we know there could be undetectable beings waving their hands in our faces as we walk down the street.

Also, the scientific method is faulty in the sense that something can exist even if it can't be replicated. For instance, I can make a basket from 1/2 court. I may do it once in my lifetime. But if no one sees me do it and I can never repeat it, does that mean it can't be done?

I think people get too snobby about science. For all we know, all of our science may be wrong in true reality. That was the case for much of classical physics.

I once had a calculus teacher that said, "If you take calculus and pass it on the first try you are very smart. If you fail and retake it and pass it on the second try you are very smart. If you pass it on your 5th try, you are still very smart."

He is also the one that said that when you are taking higher level math classes(at like the postgraduate level) that some times there is only one person in the entire room that can understand the material, and some times that isn't even the teacher.

If you think about it, a college course is like 50 hours long and you are supposed to study for 2 hours for every 1 hour of class time. So a normal person requires like 150 hours of studying calculus to understand a third of calculus(since it is usually divided into like 3 classes).

Well - there is calculus and then there is calculus. What I learned was differential and integral calculus for two-dimensional graphs, on the simplest level there is. It was calculus none the less, but of course there's more behind it, capable of causing head-aches at least in maths students, no doubt.

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Originally Posted by StephL

Well - there is calculus and then there is calculus. What I learned was differential and integral calculus for two-dimensional graphs, on the simplest level there is. It was calculus none the less, but of course there's more behind it, capable of causing head-aches at least in maths students, no doubt.

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Yes. There are proofs. Much more than just manipulating formulas.