theName()
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How do physicists do this?
HallsofIvy said:The most systematic way is this:
Do lots and lots of experiments on the specific subject you are interested in. For example Gallileo roled a lot of balls down inclined planes, measuring their speeds a different points.
Try to find some "property" that does not change or changes in some simple way. Gallileo found that the velocity of the balls changed, approximately, as the time, leading to the conclusion that v= at and so a, the "acceleration" was constant. He also conjectured that acceleration of falling balls would be constant (he used inclined planes because the velocity of falling balls was too difficult to measure a number of times), then did modified experiments on falling balls to confirm that acceleration was constant.
Other experiments with collisions between balls moving on a flat plane showed that while velocities and angles could change in complicated ways, certain combinations of those remained constant, leading to the concepts of "momentum" and "kinetic energy".
HallsofIvy said:The most systematic way is this:
Do lots and lots of experiments on the specific subject you are interested in. For example Gallileo roled a lot of balls down inclined planes, measuring their speeds a different points.
Try to find some "property" that does not change or changes in some simple way. Gallileo found that the velocity of the balls changed, approximately, as the time, leading to the conclusion that v= at and so a, the "acceleration" was constant. He also conjectured that acceleration of falling balls would be constant (he used inclined planes because the velocity of falling balls was too difficult to measure a number of times), then did modified experiments on falling balls to confirm that acceleration was constant.
Other experiments with collisions between balls moving on a flat plane showed that while velocities and angles could change in complicated ways, certain combinations of those remained constant, leading to the concepts of "momentum" and "kinetic energy".
theName() said:Are there systematic methods to finding laws of nature? How do physicists do this?
the experience can suggest us useful mathematical concepts but in any case can we deduce them from it. The experience remains of course the only criterion which validates the utility of a mathematical concept for physics…but in some sense I consider true the fact that pure reason is able to grasp Reality, the dream of the Ancients.”
My view may be expressed by saying that every discovery contains 'an irrational element', or 'a creative intuition', in Bergson's sense. In a similar way Einstein speaks that "there is no logical path... to these laws. They can only be reached by intuition, based upon something like intellectual love".
But in one point the present opinions of most philosophers and scientists seem to agree, that the inductive procedure is not, so to speak, a mechanical procedure prescribed by fixed rules. If for instance a report of of observational result is given...there is no set of fixed rules which would lead automatically to the best hypothesis or even a good one. It is a matter of ingenuity and luck for the scientist to hit upon a suitable hypothesis...I am completely in agreement that an inductive machine, which when fed with observational reports would always furnish a suitable hypothesis, is not possible...