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Comment by andars

7 years ago

Borrowing from an a old comment of mine:

On one hand, on some scales, Newtonian mechanics is correct "enough" to give results that work, and so in that sense it is just incomplete in that its domain is restricted. On the other, relativity and QM change everything. These new theories may reduce to Newtonian mechanics given certain assumptions, but Newtonian physics assumes things about the structure of spacetime that are fundamentally incorrect (e.g. velocity is not additive). In this sense, one can fairly say that Newton's mechanics are not just incomplete or missing some fine details, but wrong.

I think there is more to the foundations than just the best numbers we can come up with for a given experiment. Our numbers for the gravitational constant, for example, are pretty similar (if more precise) to the numbers in 1891, but the setting in which that number is completely changed. There is no aether, no absolute space, velocities don't add (even though it's "mostly" right on most scales we experience and measure, it is false), space and time get mixed up, etc. Those were all pretty foundational ideas just over a hundred years ago.

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andars

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whatshisface  7 years ago

>There is no aether, no absolute space, velocities don't add

There are two categories of things in that list: statements that had implications beyond what they had confirmed (the medium of light, the absoluteness of space) and an approximation (the addition of velocities.) Unsurprisingly the metaphysical interpretation of physics has not stood up to refinements in physics. The physics, however, remains true to within the bounds they knew. Likewise, the interpretation of physics is likely to change quite a bit over the next 1000 years, even 100. That's why you should never put too much stock in pop-sci articles that try to tell you that the universe is made of this-or-that. Fortunately on the philosophical side we now all realize that the interpretations are just humanizations of the knowledge itself, and are not knowledge themselves.