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Physical Intuition, Not Mathematics (2011)

realphysics.blogspot.com

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Re: Physical Intuition, Not Mathematics (2011)

#11
The problem in discussing this subject is the idea of "intuition" itself because the term doesn't have an unambiguous definition. Meaning varies from one instance to another, even one moment to the next, and disputes arise from imprecise communication.

In the example, I think what Feynman is describing, we commonly call "visualization", to be able to "see" the problem in imagination. That is no less a form of abstraction that is often vital to problem-solving. Of course, not every problem yields to this approach but it is a powerful feature of our basic cognitive tool set.

Einstein wrote that his early success in formulating his idea of special relativity was the outcome of his intuition about the physical properties of light, etc. he studied. Later on, the mathematical abstractions became more powerful, and at that point intuition about the "physical" nature of phenomena was insufficient for understanding.

But I think there are forms of intuition that apply to very abstract ideas, or what seem to be so to us. I once heard a physicist say "we never really understand higher mathematics, we just get used to it". Feynman would probably have agreed with that sentiment.

"Getting used to it" is really the equivalent of developing an intuition about the subject. I remember first learning about programming recursive functions, mind boggling in the beginning. After a while, it began to "sink in", that is, it became intuitive, I no longer had trouble "seeing" how it worked. The key is familiarity, something once strange is now digestible.

So there's nothing binary about intuition, it covers many forms of thought, and incorporates reasoning about emotion, having a "feel" for the problem in question. There are limits to our abilities, at the highest level it's genius, but there are no clear boundaries.

Re: Physical Intuition, Not Mathematics (2011)

#12
I just started reading this book, "Thinking Physics", which teaches physics the way Feynman talks about, by trying to build intuition. It asks short questions like Feynman's about the table, and expects you to think about the answer for a while, before giving it to you and presenting the physics behind it.

http://www.amazon.com/Thinking-Physics-Understandable-Practi...

Re: Physical Intuition, Not Mathematics (2011)

#13

While this is a lovely sentiment and a perfectly fine way to approach the sciences (and also engineering oriented disciplines), not all physicist think that way. There is a lot of beauty in deriving laws of nature without relying on physical intuition. A lot of beautiful results are based on purely requiring laws to be self-consistent and seeing that only one possible law is self-consistent. For instance check out wh…

QM is counter-intuitive only insofar as your intuition is naturally wired for a classical mechanics world. Given enough practice, QM eventually becomes second nature too. You pretty much _need_ to go through that process to function at the highest levels.

There's a good post by Terrence Tao about this topic, I think it was posted here some time ago:

https://terrytao.wordpress.com/career-advice/there%E2%80%99s...

Re: Physical Intuition, Not Mathematics (2011)

#14
post #13

While this is a lovely sentiment and a perfectly fine way to approach the sciences (and also engineering oriented disciplines), not all physicist think that way. There is a lot of beauty in deriving laws of nature without relying on physical intuition. A lot of beautiful results are based on purely requiring laws to be self-consistent and seeing that only one possible law is self-consistent. For instance check out wh…

QM is counter-intuitive only insofar as your intuition is naturally wired for a classical mechanics world. Given enough practice, QM eventually becomes second nature too. You pretty much _need_ to go through that process to function at the highest levels. There's a good post by Terrence Tao about this topic, I think it was posted here some time ago: https://terrytao.wordpress.com/career-advice/there%E2%80%99s...

The math behind quantum mechanics is intuitive if you view it as a generalization of probability theory to allow negative numbers. The counter-intuitive part is that the resulting system turns out to be a good model of the world.

Re: Physical Intuition, Not Mathematics (2011)

#15
This is true of programming too. You're better off learning how to code first and then learning the theory. Once you've got a few simple projects under your belt data structures and algorithms will make a whole lot more sense.

You need to learn arithmetic before you learn algebra.

Re: Physical Intuition, Not Mathematics (2011)

#16

I would be interested to know more as to how people think in the language of mathematics when deriving and reading mathematical formulas as I really struggle with it if I don't get the intuition.

Well, as a working mathematician I find that the hard part is typically coming up with the right definitions. Once you have the right concepts clearly defined (in terms of things you already know), the actual new ideas tend to arise with ease.

Similarly, it is often the case that new fields of mathematics arise from someone defining a new concept that was previously imprecise. Once you have the right language to discuss something, discovering its properties becomes much more straightforward.

Re: Physical Intuition, Not Mathematics (2011)

#18
Intuitions are insights (hints) from so-called ancient, non-verbal (pre-linguistic) instinctive "knowledge" or "genetic memory". It is not only the kind of knowledge of how birds "know" how to make nests or men know to run out of building when earthquake happen (without any prior training), but also intuitive knowledge about the nature of reality, properties of physical environment, which has been "trained" before any language, even before human species has been evolved (we share "pre-cortex" brain centers with our ancestors which were shaped by environment). This is where intuitions are coming from.

Re: Physical Intuition, Not Mathematics (2011)

#19

Related to this, there's a fair amount of research on the connection between embodied cognition and the learning of physics (and mathematics), as well as examples of 'embodying' physical forces and laws. An example from Hans Freudenthal is from a standard physics question. If there are books on top of a table, what are the forces acting on the books? Most all students draw the downward force of gravity, but some forg…

The problem I have always had with the analogy of a person holding up the books with their back is that a table doesn't have to do "work" to hold up the books, but a person does. They table isn't burning any calories.

Re: Physical Intuition, Not Mathematics (2011)

#20
post #13

Earlier quoted context omitted.

QM is counter-intuitive only insofar as your intuition is naturally wired for a classical mechanics world. Given enough practice, QM eventually becomes second nature too. You pretty much _need_ to go through that process to function at the highest levels. There's a good post by Terrence Tao about this topic, I think it was posted here some time ago: https://terrytao.wordpress.com/career-advice/there%E2%80%99s...

The math behind quantum mechanics is intuitive if you view it as a generalization of probability theory to allow negative numbers. The counter-intuitive part is that the resulting system turns out to be a good model of the world.

http://www.scottaaronson.com/democritus/lec9.html

The above is a good accessible exposition of this perspective. Though it would help to have some acquaintance with ordinary probability as well as basic linear algebra.

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