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I'm not being cheeky. I'm not looking for a mathematical explanation of how to measure forces. I'm trying to figure out if humans have yet to understand what is actually happening in the space between items (those being the things that are exerting forces on one another).

So, taking gravity as an example, we know how to measure its effects, but do we actually understand what it is? I've seen it explained as a dimple in spacetime, but that's not really much of an explanation since the visualization always involves a plane with a divot into which things are falling (apparently being attracted to some unseen pulling force beneath the dimpled surface).

I know there's a very famous Feynman interview in which he quite eloquently illustrates the problem with asking "why" questions, but this isn't a "why" question, this is a "what is it" question. In this interview he describes how charged electrons line up to magnify the magnetic force, but again, that describes the effect. I'm trying to figure out what the force actually *is.

I apologize if this seems like more of a philosophical question than a physics one, but the context is analogous to my saying "do we know what light actually is" and the answer is "it's a bunch of photons traveling at a specific frequency etc. etc" I can visualize this explanation. I'm looking for something comparable for "force".

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  • $\begingroup$ I don't mean this in a dismissive way, but I think this is a "why" question - that is, one that I don't think you will find the answers very satisfying. I mean this in earnest. The more "fundamentally" you try to answer a question, the more esoteric the model that gives an accurate description... eventually you get a very accurate model, but not very enlightening in terms of the original question. I found this frustrating for years until I began to view it as a tradeoff. $\endgroup$ – anon01 Oct 21 '15 at 20:14
  • $\begingroup$ Rather, maybe "what is" is as conceptually fraught as "why" : I think physics just give a mathematical description, and if you follow the rabbit hole far enough "what" starts to lose meaning as well. $\endgroup$ – anon01 Oct 21 '15 at 20:18
  • $\begingroup$ I suppose the alternate way to articulate the question is "how do I visualize...". The problem with physics is that some concepts defy visualization (or seem to) and as a very visual person, I'm not satisfied with a purely mathematical explanation. Without a mental movie to attach the math to, it loses all its meaning. I realize this isn't physics' problem - but it is what it is. $\endgroup$ – Genia S. Oct 21 '15 at 20:32
  • $\begingroup$ "What is" questions of this sort are even more problematic than "why" questions, as Wittgenstein put it "don't ask for meaning, ask for use". This is the same conclusion Newton arrived at when after years of puzzling over the "nature" of gravity he finally declared "hypotheses non fingo". Visualizing forces has nothing to do with what they "are", indeed dimple visualization of gravity relies on experience with gravity on Earth, it simply has to produce correct intuition about mathematics of it. In GR gravity makes objects move along geodesics, so that's what is being visualized. $\endgroup$ – Conifold Oct 21 '15 at 20:45
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Gravity is largely unexplained in modern Physics. The explanation we have for the other three forces is that gauge bosons interact with each other as the means of force carrying. Gravity, however, doesn't seem to follow this model and we have yet to discover any evidence of, or implement a proper framework which would handle, the gauge-boson for gravity, the graviton.

Essentially, you either come to visualise the process as the fundamental forces of any given particle 'pushing' on other particles (which I think is precisely the vague description you find insufficient) or to imagine these 'virtual' particles (gauge bosons) being exchanged between 'real' particles, giving them momentum in so doing.

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The fundamental forces are called so because they aren't "built on" something else which we could simplify out to. The only correct answer to e.g. "what is strong force" is to say "the strong force is and it has these certain effects." It's not "made of" anything or "based on" anything or "the result of" anything. We can describe the forces by their properties and effects, but we can't currently define them as subsets of some more basic and holistic phenomenon.

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