# How physical objects (e.g. Earth and Apple) are aware and do computation about each other? [closed]

For example, in Issac Newton's famous story, how Earth and Apple are aware that they are at distance r of each other? How they can compute their movements?!

Above example is almost simple...I'm so confused how a lot of very complex computations take place around us which only expert physicists and mathematicians may understand some of them and even super computers can not simulate them!

Do Physical objects have intelligence? Do they know Mathematic?

Simply, how the Earth and the Apple are aware about themselves and can compute what should be happened in future?

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## closed as off-topic by Kyle Kanos, John Rennie, Brandon Enright, Qmechanic♦Jan 24 '14 at 18:55

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This should be moved to metaphilosophy.stackexchange –  Carl Witthoft Jan 24 '14 at 15:38
This question appears to be off-topic because it is about philosophy and not physics. –  Kyle Kanos Jan 24 '14 at 15:40
Apple computes its movement using the MacOS operating system on Macintosh. –  Luboš Motl Jan 24 '14 at 16:11
Don't anthropomorphize physical objects. They get upset and exact revenge when you do. –  Carl Witthoft Jan 24 '14 at 16:24
@Yasser: Newton couldn't answer that question, so he assumed God did it. Einstein actually made a theory of it, which helps us understand it, regardless of any deity, but it does not not require the physical objects to know that theory. –  Mike Dunlavey Jan 24 '14 at 16:32

First, people who study physics are called "physicists", not "physicians". The latter are doctors who care about other people's health.

Second, gravity is a fundamental force in Nature, along with electromagnetism, the strong nuclear force, and the weak nuclear force. So all phenomena in the world – including computation – should be explained in terms of (i.e. should be reduced to) these four fundamental forces. The fundamental forces themselves cannot be explained in terms of anything more basic because there isn't anything that is more basic; that's what the word "fundamental" means.

The OP is apparently trying to do the opposite thing, namely to explain fundamental forces in terms of non-fundamental processes such as computation. But that's not how Nature or physics works. They work in the opposite way. Computers are complicated systems with lots of elementary particles that mostly interact via electromagnetism.

Nature doesn't face any limitations of "chips with some number of transistors" because Nature is not a chip with transistors. An apple or a planet isn't a circuit with several transistors (and GPS receivers to measure their distances), either. Nature is a system where the equations such as those describing gravity hold. It's not a free decision of the apple to fall down; the external force is dragging it towards the Earth "automatically". The apple doesn't have to do anything.

When all the appropriate corrections (not only those of general relativity but also those of string theory etc.) are included, the equations of physics exactly hold (well, they only predict probabilities because the fundamental theory is a quantum theory), and even when it is difficult for us and our computers to calculate what will happen, Nature has no problems with the laws because Nature is simply not a "finite brain" similar to ours or a computer similar to one of those we possess. In this sense, when it comes to exact calculations of the outcomes of Her own laws, Nature is "omnipotent" and "omniscient" (and yes, it is also "omnipresent"), like God.

A closely analogous question, "how magnets work and what is the feeling between them?", was asked to Richard Feynman

Feynman has spent much of the time by explaining the conceptual general issues that apply here as well. We must always "believe something" (as an axiom) if we want to explain something; we reduce the questions we didn't understand to those that we did. But we must start somewhere. And fundamental forces (magnetism in his case, gravity in our case) are simply more fundamental than computers and rubber bands.

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Well, firstly I did not mean computers by word computation but I meant fundamental meta-physical mathematic which humans can ask. Secondly, I like your answer. However, it's really hard to consider distinct objects to be omni(present,scient and potent)! –  Yasser Zamani Jan 24 '14 at 17:39
Hello. I only said that Nature was omnipotent, omniscient. Apples and planets are just small parts of Nature but the ability to compute the implications of the laws of physics isn't "confined" to an apple (or to the Earth) in any sense. All of Nature - which you may imagine to be infinite - is computing the right behavior for all the objects within it. –  Luboš Motl Jan 24 '14 at 17:57
Otherwise I have trouble with your statement that "you didn't mean computers by the word computation". Pretty much by definition, a device or agent that does computation is a computer. It may be a computer working on one architecture or another but it is a computer, otherwise it couldn't do computation. So if you were talking about computation, you were surely talking about some computers, too. Nature isn't a computer even in the most general sense; it doesn't need any "algorithms" to compute. Algorithms are only needed for computation - that is reduced to something more basic. –  Luboš Motl Jan 24 '14 at 17:59
But the laws of Nature - like, in the classical approximation, Newton's laws of mechanics involving the gravitational $1/r^2$ force - are not being reduced to any more basic processes in Nature because they are among the most fundamental processes we know in Nature. - BTW I would add that many people, sometimes considering themselves professional physicists, want to imagine that the Universe is a computer for the same reason as you listed: they think that it's hard to compute with many precise real continuous numbers because it's hard for them. But for Nature, it's trivial! –  Luboš Motl Jan 24 '14 at 18:01
It depends how you define "intelligence". Nature surely has "some kind" of intelligence - after all, it's capable of producing all the interesting phenomena and all the behavior of intelligent creatures like some of us. However, the intelligence needed to move things right doesn't require any transistors or neurons or anything like that to be connected. So for any anthropomorphic definition of intelligence, the answer is that Nature has no intelligence. It just doesn't work like a human brain or a computer. The word "intelligence" was designed to grade humans and puppies only, not Nature. –  Luboš Motl Jan 24 '14 at 19:03

Well Yasser, I will be talking mainly about gravity as it is the easiest to explain. Gravity is a physical law that exists from before and its an integral and pre-existing component. When I was about 9 years old, even I used to think how does electricity know which path offers less resistance. Unfortunately, as of now we do not know the reason for gravity. An object or mass just warps the space-time around it and there is no computation needed. Its just a force that has existed since the big-bang.

I will give an example. Suppose you throw a ball horizontally to the earth's equator, the ball doesn't compute anything when it falls. It just experiences a force which pulls it towards the earth. I don't get where is the need for any computation.

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There is no "reason" for gravity to exist. –  Carl Witthoft Jan 24 '14 at 16:25
There is a reason but we do not know it yet. Please do not kill the curiosity. –  rahulgarg12342 Jan 24 '14 at 16:44
Even if we name it gravity, again I do not understand how gravity see these two distinct objects with no eye and how policy their movement to each other?! –  Yasser Zamani Jan 24 '14 at 16:51
@YasserZamani I am sorry but its something which cannot be expressed and you need to think about it for some time. Gravity is only a name given to it. When two magnets get attracted or repelled, its not they who do it, its their property. Its an inbuilt property. Sometimes there are things which have no reason for. That is why there was a suggestion that we move this to metaphysics. –  rahulgarg12342 Jan 24 '14 at 17:33
@Carl please do not comment if you do not know. The reason for gravity is still being researched on and there is a possibility that there is a reason. Thats what I meant. There is no need to fight over such silly topics. The purpose of physics is itself to find about your surroundings and the reasons for the findings. –  rahulgarg12342 Jan 24 '14 at 18:32

This is not (may not be) how gravity really works but let us pretend it is. This is to serve as an example of how objects can follow complicated mathematical laws without "knowing mathematics".

Let us imagine that every object with mass constantly sends out a large number of "mass particles" in every direction. If this particle bumps into another object with mass it will give it a small pull (normally bumps give a push but this one pulls). So the second object will get pulled toward the first one. But only objects with mass can receive this pull so it pulls the first object toward it as well.

If we try to calculate the amount of force that a body feels from another body we just have to add up all of the particles bumping into it.

If body A is twice as massive it will give off twice as many particles and the force will be twice as great F is proportional to the mass of body A.

$$F \propto M_A$$

If body B is twice as massive it will be able to absorb twice as many particles and the force will be twice as great F is proportional to the mass of body B.

$$F \propto M_B$$

If the two bodies are twice as far away from each other they will absorb a quarter of the particles, (inverse square law).

$$F \propto \frac{1}{d^2}$$

Putting it all together we get:

$$F \propto \frac{M_A M_B}{d^2}$$

And multiply in some constant to get from proportional to to an equality.

$$F = \frac{G M_A M_B}{d^2}$$

As you can a relatively complicated description of the system can arise naturally from simple interactions between particles.

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Well, but why do you assume there is no need to computation when it's difficult for us to formalize it?! –  Yasser Zamani Jan 24 '14 at 16:53