Intuitive physics

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  • #26
hellfire
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I would like to make a short comment (hopefully understandable despite of my mediocre english).

When I read the term ‘intuitive physics’ I must think on a mainly qualitative understanding of nature. I understand here 'qualitative' as opposed to 'quantitative', which is rather less intuitive. May be easy mathematical descriptions can provide an intuitive understanding, but intuition stops working somewhere where heavy math starts.

In the modern european culture, starting from the XVI century, there is a tendency towards quantitative description of nature leaving more and more the qualitative explanations.

A last example of battle between qualitative and quantitative pictures of nature is given by the contraposition between Goethe’s and Newton’s theories of light in the XVIII century.

In essence, the qualitative method considers subject and object as a whole and not sepparable. In the quantitative method analysis and objectivity are the main features. For the qualitative method analyzing means beaking a natural connection between subject and object given by the sensorial experience. This (sensorial experience) should be (accoding to the qualitative method) the ground of the physical understanding and the way to the truth (and not analysis and mathematical modelling as according to the quantitative method).

This shall be just an historical exposition. History of science proves that this qualitative method is definitely be wrong in some aspects, but this method was inequivocally beautiful. We won a lot with modern physics, but we must be aware that we lost an important link to reality.

Regards.
 
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  • #27
marcus
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your english is fine, hellfire, completely understandable

this is Carla's thread----you and Carla may have large areas of agreement and, by discussing,each can help the other to think---and Carla can decide what is relevant

I dont know about Goethe's theory of light. I thought Newton did not have a good theory. Maybe Goethe was not right either.

I am a fan of Christian Huygens (1629-1695) and I think he had good ideas about light. He also conceived of an internal combustion PISTON AND CYLINDER ENGINE but his idea was to use gunpowder instead of petrol-and-air as we do today. His assistant Denis Papin ran off to England and helped invent the steam engine.
Also Huygens estimated the distance to the bright star Sirius. He did it by a strange method and got the wrong answer but it was the first attempt to measure the distance to a star, besides the sun. He tried to think of ways to fly---and even about life on other planets, he made clocks and telescopes.

Huygens had extremely good ideas about light. And so did Robert Hooke, and a medical doctor named Thomas Young 1773-1829.

I think you have to allow for human passions. Nothing is "lost" by discovering mathematical models if they arise from a love of nature and a strong desire to learn her secrets. If the models are not simple and beautiful enough they should eventually be replaced by better ones. A clumsy model is only a temporary expedient.

It is also possible to write bad poetry. Neither mathematics or poetry is perfect or works all the time. How did Goethe explain light? Perhaps he was right!

Feynmann has argued against the viewpoint that physical understanding (of how atoms work) diminishes enjoyment of nature. Feynmann maintained that he just had MORE ways to enjoy a sunset because he could see the red clouds as well as a painter (and indeed he was a painter sometimes) and ALSO he could see in the sunset the beautiful mechanism by which the blue light is scattered sideways as the light goes thru the atmosphere so that mostly only the red light reaches us. Also when he was at the beach, asserted Feynmann, he just had MORE to enjoy because he could see and hear the waves and enjoy the sand between his toes like anyone else but also he could appreciate other facets and dimensions of it

...In the modern european culture, starting from the XVI century, there is a tendency towards quantitative description of nature leaving more and more the qualitative explanations.

A last example of battle between qualitative and quantitative pictures of nature ...
I dont think there has been a "battle"...
One should have both kinds of understanding and descriptions, as much and as clear as possible.
If modern Europeans are leaving qualitative description of life they are making a big mistake.
But I dont think they are...when they go to the beach they probably not thinking about wave equations and atmosphere dynamics and how the sun makes light shining on the water and how the water molecules reflect it etc. The modern Europeans I know do not have a "tendency towards quantitative description" of the beach. Though it wouldnt hurt them if some did, or so I think

---------------
there are many depressing tendencies in the world and some very valuable things are being lost,
but the gradual improvement in mathematical models (and ability to display the results graphically) is not one of the depressing things, more on the other side---something hopeful

Carla, on the other hand might have a totally different opinion! So maybe you will get some very differnt responses :smile:
 
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  • #28
hellfire
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Well, marcus, you may be right that there was no battle at all, but I belive there was sometimes a battle, or at least passionated discussions regarding the role of quantitative methods for the understanding of nature. I think the origin of these can be traced to Plato and Aristotle, with the different roles of sensorial experience in knowledge. Anyway, I am not an expert in history of science and I cannot be more profound here.

On the other hand may be you misunderstood me. I was not talking about life, but about science. Of course nobody thinks about mathematical models when swiming in the sea or being in the beach, but, note: no scientific theory relies today on physical feelings, or on anykind of role of the subject when explaining something.

For example: as you probably know, the ancient greeks postulated the world to be made of earth, fire, water and air. We may laugh about that from our quantitative and analitic way of thinking, but it is subtle: it depends only on which point of the distance between object and subject you are focusing. Their focus was near the subject and they thought that the different categories of sensorial feeling shoud determinate, or at least give clear hints about the nature of the objects. The next step is obvious: just look in yourself and find out which categories of sensorial feeling you may experience and then try to extrapolate to reality.

I am confident that something like this is definitely lost in the occidental culture, means a different kind of relation between subject and knowledge, a different weighting. Whether this can be regarded to be more intuitive than modern physics is another question. In my oppinion it may, it depends what we understand under the term intuition.
 
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  • #29
marcus
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now I see better what you mean, hellfire, and if I understand you
correctly I think you have a good point.
just talking about SCIENCE it seems to me that
there has been a real shift towards mathematical description and
modeling

and not merely a shift towards emphasizing quantities
but a shift towards more sophisticated algebra and even subtle geometry

Kepler circa 1618 is often for me the test if something is true.
For over 15 centuries before him they had the Ptolemaic system which had plenty of quantities! It had all the radiuses of all the spheres! It had all the time periods of all the cycles! So if one just focuses on SCIENCE as you suggest you have them using lots and lots of QUANTITIES for 15 centuries and making very good quantitative predictions.

Kepler made a couple of subtle changes. It was not to be circles anymore, instead it was to be ellipses. You could even say it was a QUALITATIVE change that he made, to go from circles to ellipes and to get rid of all the extra spheres.

[the Copernicus model goes back to 250 BC and Aristarchus, and it does not actually work because it uses circles, so mars will not fit.
the really new thing was not Copernicus but Kepler, and it was a qualitative change]

Another change was Kepler discovered that the planet's distance from sun was not merely straigt-line proportional to its year-period. He found a relation that is SUBTLY DIFFERENT from a straight line. He discovered the distance from sun is 2/3 power of the period.

Both these moves are in the direction of more sophisticated math----circle changing to ellipse---linear, square, cube algebra moving to more subtle 2/3 power algebra.

One of the main goals in improving a scientific model is to get rid of numbers.
One sees the same progress in 20th century particle physics and in the replacement of Ptolemaic model. In the Ptolemaic model one had to specify more than twice as many number. Radii for all the spheres AND time periods for them to turn. Starting in 1618 more than half those numbers went away because you only had to list the periods of the planets and they would imply the distances from sun.

The smarter the model, the fewer numbers it needs to have input before it can start to run and make predictions

(Well there are other criteria of elegance too, but that is one of the main ones.)

So I would not call the trend, since 1618, one from qualities to quantities----I would see it as one from verbal explanation to mathematical modeling.
I see mathematical models as highly qualitative and capable of subtlety. there is a rich diversity ways to model things
and even seemingly little differences, like between circle and ellipse
can make a change

or between the 1/2 power (the square root) and the 2/3 power

before 1618 one had verbal classifications of materials to try to explain why some would burn, why some would melt or vaporize, and others would not, alchemy.
eventually there is an atomic model which roughly predicts which reactions happen readily and which combinations are possible, chemistry.
the chemical model uses numbers----numbers of electrons in the outer shell, for the most part, and associated valences.
there is less ad hoc stuff to remember and more that is predicted just by the atomic number, or the electron shell.
Carbon is Mr. 6, Nitrogen is Mr. 7, Oxygen is Mrs. 8. You almost can forget their antique names and just call them 6,7, and 8. And then these number-names will tell you things about how they behave.

Yes, I see a trend away from verbal classification and towards mathematical modeling----and also a process of qualitative refinement within the mathematical models. a process models of getting more varied and predictive and less clunky.

maybe this is so obvious to people it doesnt need to be said!
I will post it and erase later if it seems superfluous.
 
  • #30
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Just to let you know, I've started a new job. It's taxing the living daylights out of my time and energy so hard to give valuable input to this thread at the moment. Might have to resign myself to weekends for the moment. A pity, at a brief glance, both of you have added something from two unique and equally valid perspectives which makes for interesting reading and the difference in culturual background is a plus in my opinion.
 

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