mercredi 21 septembre 2016

Feynman's Invisible Angels

This is a scientific/philosophical question. I'm curious about the reactions/criticisms from the physics community.
I called it Feynman's Invisible Angels, with Angels sorta having the same meaning as Maxwell's Daemon. It originally came from this quote :

Quote:

Originally Posted by Richard Feynman, Character Of Physical Law
The next question was - what makes planets go around the sun? At the time of Kepler some people answered this problem by saying that there were angels behind
them beating their wings and pushing the planets around an orbit. As you will see, the answer is not very far from the truth.
The only difference is that the angels sit in a different direction and their wings push inward.

When Richard Feynman explains newtonian orbital mechanics, he explains it from the context of how the concept of 'force' changed from Aristotle to Newton.
Aristotle believed that in order to keep a body moving, a force needs to be applied.
This seems to be in concordance with the world around us : After all, we really do need to keep pushing things in order to keep them moving.
What Aristotle missed here was that it's the influence of friction that causes a body to slow down over time; Where there no friction, a body would just keep
coasting forever. And that's Newton's first law : A body in motion will continue to move with a uniform velocity forever, unless there is a force active.
So, in newtonian orbital mechanics, the planets are moving through a (near) vacuum and therefore do not need a force to keep them moving; They would move in a
straight line anyway. Instead, the force of gravity is applied at right angles to the motion causing the planet to 'fall and miss the ground' continually.
(In newtonian mechanics you can say that due to the fact that the force applied is always at right angles to the motion, no physical work is done, no
energy is converted, so the motion of the planets is perpetual.)
Of course, more sophisticated theories of mechanics have been developed but all they really do is provide a better approximation and since no complete
physics theory has emerged the very definition of the concept of force cannot be claimed to be understood, which is why Feynman uses the example of an
Angel pushing the planets as a base image for clarification, as well as raising awareness for the essential irony : Isn't a force just a sophisticated
version of an Angel (pushing or pulling) in the absence of any real explanation?
What is a force? We don't have a complete theory of physics and the concept of force, or curved spacetime, which is a more sophisticated version of the same
idea, only exists as a purely mathematical notion. And since we also have no idea why mathematics is unreasonably effective the final philosophical result
is that we still don't know what physics concepts like force actually are.
But where did they originate? Originally, physics is simply observing the world around us, pragmatically, and for this reason the concept of force equates to
a push or a pull. The push or the pull that is required to keep a body in motion, practically. So we've returned to Aristotle.
The observation here is that due to the final unknowability of the concepts there's no way around having to explain it starting from a mere pragmatic
push or pull notion.
This is already true from an educational perspective; Just try to explain newtonian mechanics without bringing in practical notions like that.
So by using the Angels Feynman is able to explain orbital mechanics effectively all the while communicating this essential philosophical dilemma and even
putting it in a historical context. (What a Master Educator! Unfortunately much of his Wisdom is lost because many students nowadays hate Angels, a priori,
so all the subtleties are lost on them.)
The hope of many physicists is of course that one day we might be able to get rid of those vague notions of having to start with a push or a pull; That
some complete theory will give them a complete definition.
I conjecture that this is impossible; That a complete physics theory doesn't exist.
This means we'll never get rid of having to start from a pragmatic perspective.
Observing this I concluded that it might be better to reverse the emphasis. To start from explaining it in terms of the most pragmatically effective theory of
newtonian Angels where the concept of using Angels isn't just used for ease of explanation, but because the incompleteness of physical theory forces us to
reformulate it in that way.
The ultimate incompleteness of physics law justifies the usage of pragmatic concepts like 'people pushing and pulling' which naturally evolves into
Angels when considering cosmic things. That is, in the absence of a complete physics theory, pragmatism should be our guide, as well as elegance and beauty.
Now, The motion of the galaxies, is where all physics theories fail. It has not been possible to account for the fact that a lot more gravity is required
to explain the motion of galaxies; The extra mass isn't observed and any attempt to rectify any physics theory, not just newtonian mechanics, without postulating
invisible mass has turned out to violate fundamental principles like Symmetry/General Invariance.
This is important since absence of Symmetry in physical law usually boils down to it claiming that the conserved quantities aren't conserved, which means
practically that you can create energy from nothing.
Observing that the theories all become absurd and that the extra mass just isn't there leads to the conjecture that continuing in that direction
implies absurdity. You'd have to abandon either observation or measurement as a basis for science, or you'll end up arguing for violations in Symmetry
in such a way that absurdities like energy-from-nothing arise.
In that case, basing the further development of physics on a pragmatic, fuzzy, aesthetic concept becomes a necessity. The further development of physics law
then becomes the search for the most elegant, beautiful and pragmatic formulation of the theories; It will no longer be about trying to find the TOE in
the purely mathematical sense of the word.
For these reasons, I have proposed Feynman's Invisible Angels as a basis for this new aesthetically driven formulation of physics since it's ultimately
the concept of 'force' that is the easiest to anthropomorphize, and it's ultimately the concept of 'gravity' whereon the mathematical theories fail.
And since it's about a return to the concept of 'force' in the pragmatic sense it's best to emphasize the most pragmatic of all formulations of physics :
That of Newton. And finally the anthropomorphization of cosmic things naturally leads to Angels.
It's important to observe here that other forms of fairy dust, like Dark Matter, will not do since we've already ascertained that a return to the pragmatic
is required in case of a fall into absurdity, theories that predict that you can create energy out of nothing or theories that claim things contrary
to observation, so we need to start from as basis of anthropomorphization to make the incompleteness and therefore final undefinability of the ideas of physics,
all those concepts like force, momentum, energy etc. unproblematic.
And since the choice here really does seem to between absurdity (Dark Matter) vs. absurdity, but a nice pragmatically usable image that doesn't lose any of the
old formulations of physical theory (Feynman's Invisible Angels), I posit that the latter is a superior theory.
Dark Matter? No. There are Feynman's Invisible Angels. And they are flapping their wings faster. Capiche?


via International Skeptics Forum http://ift.tt/2cu3cBx

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