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One perspective is that physics at this level is purely descriptive. Hawking, in his response to Penrose in the book The Large, the Small, and the Human Mind,

One perspective is that physics at this level is purely descriptive. Hawking, in his response to Penrose in the book The Large, the Small, and the Human Mind, writes: "[I believe] that physics theories are just mathematical models we construct, and that it is meaningless to ask if they correspond to reality, just whether they predict observations." It is a common mistake for people to confuse a physical theory like Newtonian mechanics or general relativity for reality itself. I feel like an explanation of gravity at this point is a metaphysical question that is outside the realm of science. It may be that science ultimately comes up with an explanation, but it will be in terms of something else and you will naturally be led to ask, what is an explanation of THAT thing? As for your description "... two objects attract each other ...," this is an outdated, Newtonian way of thinking about gravity. It involves a "spooky" action at a distance. As I understand it, it is generally thought that the best theories are purely local ones. General relativity is the proper local formulation of gravity: masses curve space, and all objects move in "straight" lines (that is, geodesics) through curved space. Newton was right about inertia. There might be more sophisticated ways of understanding gravity in quantum gravity, but that's beyond me.

shawndumas 16y ago
[I believe] that physics theories are just mathematical models we construct, and that it is meaningless to ask if they correspond to reality, just whether they predict observations." --Hawking That's where I'm heading... I am slowly coming to the point, which is hard to take-in emotionally, that that’s all the justification we have for any scientific theory.
- Gormo 16y ago
  That's pretty bog-standard empiricist epistemology: reality is what it is, irrespective of our understanding. But it's very hard for the human mind to fully comprehend that, because the mind can only operate on ideas, not the reality that those ideas represent. We are incapable of distinguishing the world itself from our understanding of it, except through a kind of cognitive dissonance: tentatively accept certain ideas as "true" in order to apply them to useful ends, while maintaining a conscious skepticism of any of them actually being "true". This is itself a very hard balance to maintain. Many people tend to gravitate toward the polar extremes, becoming either ideologues who thoroughly conflate the entirety of reality with their subjective ideas, or "just the facts" cynics who dismiss anything remotely theoretical.
- mian2zi3 16y ago
  I know what you're going through. I was deeply troubled (still am, really) when I first read Hume and started thinking about the Problem of Induction. You might enjoy taking a look at Hume's Inquiry on Human Understanding. (I'm sure you can find it online.) I also found Wesley Salmon's essay "An Encounter with David Hume" useful. I originally read it here: http://www.amazon.com/Reason-Responsibility-Readings-Problems-Philosophy/dp/0534573525#reader_0534573525 http://www.amazon.com/Reason-Responsibility-Readings-Problem... (This book has several other good essays in philosophy of science.) Salmon's essay seems to be reproduced here: http://kslinker.com/An_Encounter_with_David_Hume.htm http://kslinker.com/An_Encounter_with_David_Hume.htm
- aamar 16y ago
  Scientific theories aren't so different from explanations of any other sort. None of them (whether science or otherwise) are descriptions of "reality"; they are all models. But anyway that seems off to the side of what you were asking for, which is an explanation (i.e. reasons or causes), not direct correspondence to reality, which is a different issue. Scientific theories, like other theories, do have "explanations", in the sense of broader or more general theories. It's true that there are some scientific theories (arguably including gravity) that do not yet have good explanations, but I'd guess that in all such cases, people are still looking.

shawndumas 16y ago

[I believe] that physics theories are just mathematical models we construct, and that it is meaningless to ask if they correspond to reality, just whether they predict observations." --Hawking That's where I'm heading... I am slowly coming to the point, which is hard to take-in emotionally, that that’s all the justification we have for any scientific theory.

Gormo 16y ago
That's pretty bog-standard empiricist epistemology: reality is what it is, irrespective of our understanding. But it's very hard for the human mind to fully comprehend that, because the mind can only operate on ideas, not the reality that those ideas represent. We are incapable of distinguishing the world itself from our understanding of it, except through a kind of cognitive dissonance: tentatively accept certain ideas as "true" in order to apply them to useful ends, while maintaining a conscious skepticism of any of them actually being "true". This is itself a very hard balance to maintain. Many people tend to gravitate toward the polar extremes, becoming either ideologues who thoroughly conflate the entirety of reality with their subjective ideas, or "just the facts" cynics who dismiss anything remotely theoretical.
mian2zi3 16y ago
I know what you're going through. I was deeply troubled (still am, really) when I first read Hume and started thinking about the Problem of Induction. You might enjoy taking a look at Hume's Inquiry on Human Understanding. (I'm sure you can find it online.) I also found Wesley Salmon's essay "An Encounter with David Hume" useful. I originally read it here: http://www.amazon.com/Reason-Responsibility-Readings-Problems-Philosophy/dp/0534573525#reader_0534573525 http://www.amazon.com/Reason-Responsibility-Readings-Problem... (This book has several other good essays in philosophy of science.) Salmon's essay seems to be reproduced here: http://kslinker.com/An_Encounter_with_David_Hume.htm http://kslinker.com/An_Encounter_with_David_Hume.htm
aamar 16y ago
Scientific theories aren't so different from explanations of any other sort. None of them (whether science or otherwise) are descriptions of "reality"; they are all models. But anyway that seems off to the side of what you were asking for, which is an explanation (i.e. reasons or causes), not direct correspondence to reality, which is a different issue. Scientific theories, like other theories, do have "explanations", in the sense of broader or more general theories. It's true that there are some scientific theories (arguably including gravity) that do not yet have good explanations, but I'd guess that in all such cases, people are still looking.