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Old 09-11-2017, 06:05 PM   #16
Keatah
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Science seems to explain the effects and behavior and characteristics of gravity. But it doesn't tell us how it works or how to interface with it beyond using the tired terms of "mass" and "space-time".

In complex things there are often multiple ways of describing what is seen. All can be accurate because they are simply observations, not explanations of how they work.

Last edited by Keatah; 09-11-2017 at 06:08 PM.
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Old 09-12-2017, 03:50 PM   #17
Thunder Chicken
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Originally Posted by Andy44 View Post
 But then magnets, how do they work?!
I remember asking this question to a physics professor in college. He launched into the lecture of electron orbitals and fields and such. I interrupted him and said he was describing the mathematical model that predicts the force, and I then asked HOW do they work?

His response: "Oh, that. Damned if I know."

He was a great professor.
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Old 09-12-2017, 05:41 PM   #18
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I then asked HOW do they work?
Actually - what would you accept as a valid answer to how something works if it's not math?

(genuinely curious - I think this is a difficult question, I have some ideas of my own, but I'd rather hear yours first).
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Old 09-12-2017, 05:42 PM   #19
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Love the discussion! You guys lost me long ago, but this thread tells quite a lot about the OF community
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Old 09-12-2017, 07:07 PM   #20
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Originally Posted by Thunder Chicken View Post
 I remember asking this question to a physics professor in college. He launched into the lecture of electron orbitals and fields and such. I interrupted him and said he was describing the mathematical model that predicts the force, and I then asked HOW do they work?

His response: "Oh, that. Damned if I know."

He was a great professor.
This reminded me of Feynman's answer on magnets in a BBC interview.



As far as I can tell, the HOW questions can be answered with math.
The WHY questions are much more difficult.
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Old 09-12-2017, 08:24 PM   #21
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 Actually - what would you accept as a valid answer to how something works if it's not math?

(genuinely curious - I think this is a difficult question, I have some ideas of my own, but I'd rather hear yours first).
Well, something akin to how I can describe how an internal combustion engine works without using any math.

But my post asking how magnets work was a reference to an internet meme; I was attempting to demonstrate through humor the fact that no matter what answer you give to the question about how gravity works, you will spawn new questions.

If I could prove to you that God exists, even that would prompt the question, "So how does the supernatural work?"
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Old 09-12-2017, 09:28 PM   #22
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True, it might be considered we don't have an equation that accurately predicts humans

... Yet, here we are
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Old 09-13-2017, 04:54 AM   #23
Thorsten
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Well, something akin to how I can describe how an internal combustion engine works without using any math.

Please humor me - how would you do that?
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Old 09-13-2017, 05:31 AM   #24
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 Please humor me - how would you do that?
Fuel and air are mixed inside a cylinder and ignited, creating hot gasses which expand, pushing a reciprocating piston attached to a rod which turns a crankshaft. The rotation of the crankshaft operates valves that allow the intake of the fuel-air mixture and the exhaust of the spent gasses.

I could go on, but you get the idea. No math is needed for a simple layman explanation. Lots of mechanics can tell you how an engine works without knowing much about the math needed to design it or perform a detailed analysis of it.

Similar to the way we describe satellite motion by analogy to a bucket swung around in your hand. The force of your hand on the bucket keeps the bucket moving around you in the same way gravity keeps a satellite moving on a curved path around a central body.

Simple concept, until you ask "but wait, how does gravity actually work?" which is the OP's question.
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Old 09-13-2017, 05:45 AM   #25
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Simple concept, until you ask "but wait, how does gravity actually work?"
Let me play devils advocate here:

Fuel and air are mixed inside a cylinder and ignited, creating hot gasses which expand

But how does this actually work? Why does stuff ignite, why does ignition make anything hot (and what is heat in the first place?), and moreover, why do hot gases really expand?

So what you mean by giving an explanation here is providing a link to things we experience in daily life and hence do not question any more. We've all seen flames, so we don't really wonder how they really work. To us, the idea that hot gases expand is sort of obvious (though it wasn't through most of classic history). We know expanding stuff can push things.

In that sense, you can also explain gravity - it's the pull we feel, standing on Earth (and some of us might even have felt the lack of it during short free-fall periods). We all know what it is just as we know what a flame is or what heat is - unless we ask the question what it really is.

So I think if you take 'explanation' in the sense of 'link to stuff we know from experience', then explaining gravity affecting a satellite as the same force that pulls us down in everyday life is valid.

Yet you seem unhappy with it - so there must be more to the meaning of 'explanation', no?
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Old 09-13-2017, 03:38 PM   #26
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 This reminded me of Feynman's answer on magnets in a BBC interview...
Fantastic answer
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Old 09-13-2017, 05:02 PM   #27
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 Actually - what would you accept as a valid answer to how something works if it's not math?

(genuinely curious - I think this is a difficult question, I have some ideas of my own, but I'd rather hear yours first).
I'd say biological evolution (by natural selection) - because although it's basically mathematics at its core (well maybe statistics), it's so intuitive in the way it works I think it becomes cumbersome to try and express it mathematically.

(This may not be a good answer though - after all people have been doing genetic programming in AI, etc. for years. They probably do have a reasonably tidy description.)
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Old 09-13-2017, 07:14 PM   #28
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 I'd say biological evolution (by natural selection) - because although it's basically mathematics at its core (well maybe statistics), it's so intuitive in the way it works I think it becomes cumbersome to try and express it mathematically.
Evolution requires population genetics to have any rigor. And population genetics is statistics from top to bottom. It's true that you can explain evolutionary theory (of which natural selection is a part) in simple elegant language, but to be able to make predictions based on it, verify its accuracy and refine its formulation requires the rigor of mathematics, particularly when you add molecular genetics to the mix.
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Old 09-13-2017, 09:54 PM   #29
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Quote:
Originally Posted by Thorsten View Post
 Let me play devils advocate here:

Fuel and air are mixed inside a cylinder and ignited, creating hot gasses which expand

But how does this actually work? Why does stuff ignite, why does ignition make anything hot (and what is heat in the first place?), and moreover, why do hot gases really expand?

So what you mean by giving an explanation here is providing a link to things we experience in daily life and hence do not question any more. We've all seen flames, so we don't really wonder how they really work. To us, the idea that hot gases expand is sort of obvious (though it wasn't through most of classic history). We know expanding stuff can push things.

In that sense, you can also explain gravity - it's the pull we feel, standing on Earth (and some of us might even have felt the lack of it during short free-fall periods). We all know what it is just as we know what a flame is or what heat is - unless we ask the question what it really is.

So I think if you take 'explanation' in the sense of 'link to stuff we know from experience', then explaining gravity affecting a satellite as the same force that pulls us down in everyday life is valid.

Yet you seem unhappy with it - so there must be more to the meaning of 'explanation', no?
You're making my point for me.
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Old 09-14-2017, 05:45 AM   #30
Thorsten
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You're making my point for me.
Well, actually I'd like to know what that 'more' is in your case.

(I posed the same question yesterday to a good friend of mine, and her reply was straightforward in the sense that it only touched calculability and predictability, i.e. the math - she wasn't at all interested in any 'really' beyond that and willing to accept a concise formulation in equations as explanation - the point of this being - we're not all the same. We don't all mean the same thing when we ask for 'how it really works' - hence the question 'What would you accept as explanation?' is rather meaningful and not just a cheap trick).
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