Is Relativity the Evolution of Classical Physics?

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Discussion Overview

The discussion revolves around the definition and scope of Classical Physics, particularly in relation to Kinematics and the inclusion of Einstein's relativity. Participants explore whether concepts like classical electrodynamics and relativity should be classified as classical or non-classical physics.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants assert that non-relativistic kinematics qualifies as Classical Physics.
  • There is a suggestion that Classical Physics excludes quantum physics, but opinions vary on whether it includes Einstein's relativity.
  • One participant defines Classical Physics as everything that is not quantum physics, including Newtonian mechanics and classical electrodynamics, but notes that relativity's classification is debated.
  • Another participant describes general relativity as a significant part of Classical Physics, while others argue it may not fit this classification.
  • A participant expresses a view that Classical Physics encompasses all physics known up to the end of the 19th century, excluding relativity and quantum theories.
  • There is a discussion about whether classical electrodynamics, discovered in the 19th century, should be considered classical due to its relativistic nature.
  • Some participants argue that relativity serves to address inconsistencies in classical physics, while quantum theory represents a more revolutionary shift.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the definition of Classical Physics, with multiple competing views regarding the inclusion of relativity and the classification of various theories. The discussion remains unresolved.

Contextual Notes

Participants express differing assumptions about the boundaries of Classical Physics, particularly concerning the definitions of classical and relativistic theories, and the historical context of their development.

askor
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Can someone please tell me what is Classical Physics?

Does Kinematics in One Dimension such as in Physics textbook is considered a "Classical Physics"?
 
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Not QM and not Relativity, I would think. Non-relativistic kinematics of macro objects would certainly seem to qualify as Classical, IMO.
 
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askor said:
Does Kinematics in One Dimension such as in Physics textbook is considered a "Classical Physics"?
Sure, kinematics is part of "classical" physics. But note that homework problems belong in the Homework section.
 
Classical physics excludes quantum physics. Depending on who you ask, it may or may not include Einstein's relativity.
 
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askor said:
Can someone please tell me what is Classical Physics?

Does Kinematics in One Dimension such as in Physics textbook is considered a "Classical Physics"?
That's not so easy to answer, because not everybody agrees on what's "classical physics". For me classical physics is everything which is not quantum physics, i.e., on a fundamental level classical physics consists of Newtonian mechanics, classical electrodynamics, and special as well as general relativity. Some people also call relativity "not classical" though.
 
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It's been said that general relativity is the jewel in the crown of classical physics.
 
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I am an old romantic of the end of the 19th century, in my opinion classical physics is all physics as they have been assembled up to the end of 19th century 1880-1900 and they don't include special or general relativity, and of course not anything quantum (quantum mechanics, quantum electrodynamics).
 
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In summary:
  • Anything that is not using special relativity, general relativity nor anything quantum is definitely classical.
  • Anything quantum is definitely non-classical.
  • Special and general relativity may be classical or not depending who is talking. Note that non-quantum electromagnetism falls into this bracket since it's an inherently relativistic theory.
 
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Delta2 said:
I am an old romantic of the end of the 19th century, in my opinion classical physics is all physics as they have been assembled up to the end of 19th century 1880-1900 and they don't include special or general relativity, and of course not anything quantum (quantum mechanics, quantum electrodynamics).
So is classical electrodynamics (Maxwell's and the Maxwellian's version of it) then classical, because it was definitely discovered in the 19th century or is not not classical, because it's the paradigmatic example of a relativistic (gauge) field theory?

Also relativity is just a smooth continuation of the "good old classical physics". It's just "repairing" the inconsistencies of classical physics as far as the spacetime description is concerned, dealing with the intrinsic contradictions between the Galilei-Newtonian spacetime structure with Maxwell's electrodynamics. All of what you call "classical physics", based on Galilei-Newton spacetime, was very quickly "translated" into its relativistic version (though it took some decades to sort out some quibbles with subjects like thermodynamics).

In contradistinction to that quantum theory was really a revolution, which indeed forced the physicists to abandon the "old romantic" deterministic worldview, and that's why I would think that it's more appropriate to count relativity to classical physics while quantum theory is really something new.
 
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vanhees71 said:
So is classical electrodynamics (Maxwell's and the Maxwellian's version of it) then classical, because it was definitely discovered in the 19th century or is not not classical, because it's the paradigmatic example of a relativistic (gauge) field theory?

Also relativity is just a smooth continuation of the "good old classical physics". It's just "repairing" the inconsistencies of classical physics as far as the spacetime description is concerned, dealing with the intrinsic contradictions between the Galilei-Newtonian spacetime structure with Maxwell's electrodynamics. All of what you call "classical physics", based on Galilei-Newton spacetime, was very quickly "translated" into its relativistic version (though it took some decades to sort out some quibbles with subjects like thermodynamics).

In contradistinction to that quantum theory was really a revolution, which indeed forced the physicists to abandon the "old romantic" deterministic worldview, and that's why I would think that it's more appropriate to count relativity to classical physics while quantum theory is really something new.
Classical Electrodynamics are part of classical physics, they were discovered in the 19th century and no one knew back then what is a relativistic gauge field theory and that CED is one such theory

The inconsistencies of classical physics were known by the late 19th century. Relativity fixed some of them and quantum physics fixed some other. If I had to choose between relativity and quantum physics as an extension of classical physics I would choose relativity of course.
 
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