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My question is basically targetting various sciences that we use to understnad the real world and how we form laws in them. For example, in physics, we first see sometthing in the real world. Let it be Newton seeing the apple fall down or anything else. It could be the fine tuned constants of nature. Now, we go on to follow a mathematical path that is based on physical reality. For example, if I ask why doesn't the law of gravitation have r^3 in its denominator, then I could we answered as ,"It also has to match up with reality". So we have this phenomena of having chosen the laws that fit reality and building math like that too if I am not wrong.

I don't remember which one, but I think it was Special Relativity that Einstein formulated purely on the basis of thought and did not keep anything to fit observed reality.

In a sense then, if I ask why a law is valid, the mathematical proof will be built around axioms ultimately. Similarly if I ask why a physical law is valid, some parts of the reasoning always involves "It is what it is".

Wasnt physics supposed to describe reality? I mean when we ask why does an object fall under gravity, most people tend to tell that it accelerates down, and describe the whole law. But then isnt that just describing what was itself formed under the process of 1st seeing nature, 2nd building a theory that purposely matches reality and 3rd using it to make predictable observations as a substitution to having to observe again and again.

It still raises the concern that Nature doesn't need to follow our laws. Moreover, our laws are guided by nature as they were formed on it's basis and observation. So, what are we really using Physics then to do? Making observations?

While I recognise that knowing the "what can it do and hows" of an object are of more practical use than the "why it does that" (although knowing why seems more reasonable to me), even for the purpose of pure scientific quest, will we be ever able to answer a true "why" question? Does everything then have a reason? What if I perpetually keep asking "why" to the responses?

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    We make observations, we imagine laws and relations between entities, we check them through experiments, we use laws and relations to predicts new facts, we revise our theories. Jun 10 at 16:53
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    SO will we be ever able to know why those laws are followed in nature without invoking unnecessary infinite universes that have all sets of laws followed in them (all possible configs) Jun 10 at 17:06
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    Mauro did not say all of that. What the conclusion is that no science can produce certainty. All any science can do is provide probability of something being true. This does not mean there is no certainty. To conclude nothing is certain would be false and an error. It just means science can't provide absolutes. Other subjects can provide some absolutes. Hence we know some absolutes exists.
    – Logikal
    Jun 10 at 18:55
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    The ancient Temple of Apollo at Delphi inscribed maxims such as "Know thyself", "Certainty brings insanity"... Socrates once said in Phaedrus that people are trying to know obscure things before they know themselves... Jun 10 at 19:39
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    If you ask a person 'why' over and over, they will get tired of answering. If you ask reality at large, all you will ever get is a deafening, perpetual silence. So, work with people, and try not to ask too many questions of something that cannot ever answer. (That's my advice, anyway)
    – Scott Rowe
    Jun 11 at 11:12

5 Answers 5

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  1. I agree with you than one can extend a series of why-questions and corresponding answers to infinite length. At which point should one stop?

  2. Usually one stops when one has obtained a physical theory, formalized in mathematical language, which explains the open questions in a certain domain of investigation.

    Examples: Newtonian mechanics (NM) for the domain of small velocities and not too small masses. Special theory of relativity (SR) for the domain of arbitrary velocities and no too big masses. General theory of relativity (GR) for arbitrary big masses, quantum theory (QM) for small masses etc.

    Most satisfying is an explanation which generalizes results obtained so far: GR generalizes SR, SR generalizes NM.

  3. Hence physics can only reduce why-questions along a finite set of steps. Then it has to stop and to explicate its finitely many axioms. They now serve as starting point to build the theory. The theory explains ‚the real world‘ if all predictions of the theory are confirmed by observation.

    One of the axioms of SR states that all observers measure the same speed of light. Other axioms of SR state that the set of events is the 4-dimensional Minkowski space.

  4. If somebody is unsatisfied with the fact that physics does not deal with ultimate why-questions, then he/she should ask himself: Which kind of final answer of my why-question would I accept?

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    Sounds wrong to me when people say that physics explains why things happen the way they do-because we FIRST take some observations, make our "laws" around them and then use them to make predictions. I am saying that then the real question we should ask is what is the underlying principle behind the existence of such laws in nature. Why does nature work the way it does-but it ultimately would also lead to an infinite line of question since I can further ask about the nature and contingency of that underlying principle which governs how nature works. Jun 11 at 7:39
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    @AveerSingh and so, mercifully, we are saved from falling in to a black hole of endless cogitation to no purpose by either getting hungry, or running out of heartbeats. Pragmatism wins out. I worry that an AI might not have our severe limitations. It could become a sort of nuclear thought bomb, like in the story, "The Magic Goes Away"
    – Scott Rowe
    Jun 11 at 11:38
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    @Aveer Singh ‚Why does nature work the way it does?‘ I suspect: One will not find an answer if one did not answer before the question posed in part 4 of my original answer. Possibly your question overexpands the range of validity of the why-question.
    – Jo Wehler
    Jun 12 at 7:37
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    In a sense, yes, we will never be able to reach an end without the introduction of divinity. My question is then why doesnt physics embrace the fact that we can't explain nature truly Jun 12 at 7:38
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    @Aveer Singh I agree: Divinity is the joker which seems to explain everything. But what does support the existence of the joker itself? From a philosophical point of view, introducing the divinity-joker only shifts the why-question one step further. See also philosophy.stackexchange.com/questions/50913/…
    – Jo Wehler
    Jun 12 at 11:42
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I don't remember which one, but I think it was Special Relativity that Einstein formulated purely on the basis of thought and did not keep anything to fit observed reality.

This is false. There were many experiments and pre-existing mathematical results which motivated Einstein for his relativity theory. For instance, one of the main experiment that motivated Einstein to think in the direction of relativity was the Michaelson morley experiment, and on the mathematical side, the Lorentz transformation found by Voigt. That's right, Einstein didn't come up with the exact transformation law between coordinate frame when a speed is fixed. He only took those rules and saw that experiment and made the connection.

It still raises the concern that Nature doesn't need to follow our laws. Moreover, our laws are guided by nature as they were formed on it's basis and observation. So, what are we really using Physics then to do? Making observations?

While I recognise that knowing the "what can it do and hows" of an object are of more practical use than the "why it does that" (although knowing why seems more reasonable to me), even for the purpose of pure scientific quest, will we be ever able to answer a true "why" question? Does everything then have a reason? What if I perpetually keep asking "why" to the responses?

We essentially assume regularity in our experience when doing science. That is, if we do a test of Newton's laws today or some time later, then it will be equally true at any time. Usually when people learn these stuff, they don't question it much because they have an assumption motivated by induction. That is, they think what they saw for all the life would be what they see tomorrow.

This reasoning is sort of flawed because it could be that tomorrow for whatever reason all the laws of physics changes for some reason beyond our current understanding, but, I think it is best to keep our worries away till such a day actually comes.

The purpose of physics is mainly have a method to predict the future in a way. How it works is that we see a few situations, now we try find models which fit that situation , and then, we see what other prediction that model can make. Now, it maybe that we find a new phenomena that our model can't explain, then we go back to the drawing board and try to tweak/ rework our model to include this phenomena into the set of calculable things.


On the purpose of Physics

The purpose of physics is usually not to give an explanation of why things are, that I think is more of a goal for spirituality/ religion. Though it may be that sometimes that one can understand complicated phenomena through simpler principle.

For example, a simple reason we can give for why things happen the way they do is from the principle that the universe is tending always to a state of disorder (higher entropy). Now, using this we can explain a many phenomena related to cosmology , but, if one were to ask "Why is it actually tending toward a state of disorder?" it may be that the answer is not there. And even if it is there, a few more "why?" then the answer is again we don't know.

The main point is to be able see how it works. It's essentially an reverse engineering process where we try to find an explanation of many complicated phenomena by simple rules. Take for example optics and Snell's laws, after observing light and it's behavior when reflecting and refracting surface, we can deduce both the Snell's law of Reflection and Refraction.

Now, to further our understanding, we can sum up the previous knowledge in the idea of time extremization. That is , we can see both the above results are the path an object would take if it wanted to move in a way that it minimized time between two points.

And, again even further, one could explain it on some Quantum theory that the probability of light going in some path is proportional to time and integrating over all paths, that of stationary time contributes the most.

We see that each level, the explanation is more sophisticated and it can be used to reason a much more amount of cases, and, in all cases a correct usage of Physics.

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  • There maybe a few grammatical errors in this answer. Feel free to edit that if you come across it Jun 10 at 20:38
  • The quantum picture can be found at end of this Feynman lecture Jun 11 at 9:34
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    OMG - Michelson–Morley experiment... The poor man never did accept that it would be equally false, today, and every day! Gack! And so, we use that non-result to detect black holes colliding in the distance now. You can't make this stuff up. And telescopes a mile underground noticing supernovas by looking for ghosts...
    – Scott Rowe
    Jun 11 at 11:28
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    @ScottRowe that tells us how, in science, the researcher who doesn't find is just as important as the one who finds, even if most people only remember the latter. I remember a Japanese Nobel prize recipient who said just that in his acceptance speech. Thought it was pretty ballsy of him.
    – armand
    Jun 14 at 4:41
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Caveat

There are some different metaphysical positions on the universe. Some have the belief the universe is a hologram, and others say it's a simulation; some believe in multiple universes. My response rejects these views as non-empirical, and I believe represents the received physicalist view on this topic.

Answer

If you subscribe to mental representations, than it's simple to understand our thinking as a map, and the universe as a mapped territory. This is known as the map-territory metaphor, and is important because a lot of thinkers commit a category mistake and confuse the two. From the article:

Polish-American scientist and philosopher Alfred Korzybski remarked that "the map is not the territory".

So, what goes on in the external, physical world, and what goes on in our minds are fundamentally two different things. Setting aside lots of complicated philosophical theory related to the mind-body duality, which addresses exactly how the physical and mental worlds relate, it is sufficient to say that for the purposes of this conversation, we just maintain that they metaphysically, they are two, different domains of discourse.

When something happens in the physical world, scientists attempt to create a scientific explanation. Setting aside exactly what that means, we can say that scientists often try to build mathematical models of what they are describing. In the olden days, these were called Laws! But the problem with irrefutable Laws, is that they have a history of being displaced, changed, or outright disproven. This is what we in philosophy call the scandal of induction which Hume is famous for, but certainly goes back to Ancient Greece. This answers your first question. The universe does not "follow" laws, but because the universe isn't an agent; such attempts to say the universe must obey our laws is confusing the territory for the map. You wouldn't draw a picture on a map and expect mountains to change in physical reality. To scribble an equation and then find the universe does not conform to it is the same in principle. Newton had a lovely set of Laws, until Einstein came up with a better set that were more comprehensive. This is a perfect example of how human reason is defeasible.

The mathematical view that dovetails nicely with this is mathematical intuitionism. From WP:

In the philosophy of mathematics, intuitionism, or neointuitionism (opposed to preintuitionism), is an approach where mathematics is considered to be purely the result of the constructive mental activity of humans rather than the discovery of fundamental principles claimed to exist in an objective reality.

Thus, physical theories which are mathematical are nothing more than constructed, linguistic artifacts that describe experience. This is in contrast to the non-empirical notions of Platonism which assert that there is some alternative physical realm of real things called numbers.

So, what are we really using Physics then to do? Making observations?

Yes. Physics makes observations, creates qualitative and quantitative descriptions, and uses them to make predictions, solve problems, and offer an explanation.

will we be ever able to answer a true "why" question? Does everything then have a reason? What if I perpetually keep asking "why" to the responses?

In the phrase "true why", true is a weasel word and doesn't really communicate anything other than your believe that some why's are better than others. As for a string why's, that's very scientific if done correctly. See Cummin's ideas in "Causal Role Theories of Functional Explanation" and an answer about it here. The universe is a big place with lots of changing parts, so yes, you can keep asking why's about it until your last breath. The real trick is making the why questions meaningful and not confusing the sorts. Aristotle got a good start on this with his Four Causes, and you might consider philosophy nothing more than the continuing pursuit of asking why.

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    So, when we study Physics, for example, we learn more about our brains than we do about the world, ha ha. It's like when you adjust a microscope or some other instrument just right, straining to reach some new level of observation, and you end up discovering the dust particles inside it, or spherical aberration or something. The harder we try, the more we discover... ourselves. The Map.
    – Scott Rowe
    Jun 11 at 11:21
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    @ScottRowe Our brains were designed (by evolution) to discover patterns in the world, because that allows them to guide us to more successful behavior.
    – Barmar
    Jun 11 at 13:15
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    @ScottRowe That's true for almost all studies including physics certainly as the ancient Shurangama Sutra insinuated: "Extremely subtle, the Adana consciousness Makes patterns of habit that flow on in torrents. Fearing you will confuse the truth with what is not, I rarely tell you of all this. With your own mind, you grasp at your own mind. What is not illusory turns into illusion..." Since you had this seed planted somewhere, that may be a reason you've been attracted to philosophy long ago... Jun 11 at 19:18
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    @DoubleKnot Perhaps so. I wanted to know a system that could help we find out what is true. The hard truth is, there is no system. But now I know how to know what is true.
    – Scott Rowe
    Jun 11 at 19:25
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    @ScottRowe Good to hear your enlightenment! Now in principle nothing can hinder you to find out the truth and truthfully answer every question on this site at least lol. Gate, gate, svaha... Jun 11 at 19:39
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Science to understand and predict reality

First, we observe that objects near Earth's surface accelerate downwards at some degree.

Then, through various experiments and measurements, we come to understand that objects near Earth's surface accelerate downwards at about 10 m/s due to gravity (but they may also be affected by other forces).

Then, when we consider an object near Earth's surface, we expect it to accelerate downwards at about 10 m/s due to gravity. Now we can build structures that use this information, that would work if this gravitational acceleration is indeed correct.

It may be true that the understanding we gain doesn't accurately reflect reality, and that reality may not be that consistent, but this process, and assuming that reality is consistent, has led to most man-made things, from computers to buildings to medicine to cars.

The "why" may not be necessary for the above, but it does help.

Science to explain why

Science has some capacity to explain why things are the way they are, but perhaps not quite to the degree (or as directly or quickly) as you'd like. To be able to explain why with science, one must be able to come up with a model to explain observations, and there must be sufficient evidence for that model to be the most likely explanation for the evidence. This is only really works if you can understand the underlying mechanisms well enough.

You're welcome to keep asking "why" for as long as you want, and indeed trying to figure out the "why" is good, but science can only tell you so much (and if you want to use a different method to answer the question of "why", I would say that method would need to have proven to work to a similar degree that science has, if you want to be justified in relying on it).

Consider gravity again as an example.

After we've observed gravity on Earth's surface, we've also observed lower gravity further from Earth's surface, we've observed the Earth rotating around the Sun, and the Moon rotating around the Earth, among many other observations.

Given the above, the "why" of gravity we've come up is that these large objects pulls other objects towards themselves (or, more technically, they bend spacetime), and we've come up with a formula to describe this.

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I don't remember which one, but I think it was Special Relativity that Einstein formulated purely on the basis of thought and did not keep anything to fit observed reality.

Far from it! The theory of special relativity was created to address a failure of the best prior theories to match observed reality in the Michelson–Morley experiment.

Physicists had observed that waves—like ripples in water, sound in air, etc.—are a phenomenon arising in a medium, and followed various rules that were reasonably well-understood for centuries. Light too seemed to follow many of these rules. So physicists hypothesized that light must be a phenomenon arising in a medium, called the luminiferous aether.

The luminiferous aether model served to predict some behavior of light, but implied the existence of a distinguished frame of reference at absolute rest—as if everyone were on a windowless train traveling in an unknown direction at an unknown speed, but there is a stationary ground so if you walk in a certain direction at a certain speed on the train, you would be at "absolute rest" even though people sitting down on the train appear to be moving relative to you.

In this model, light in the train should act like sound in the still air outside the train: it should appear to propagate at different velocities depending on how you're walking around on the train. So you should be able to measure the speed of light in parallel to the train versus the speed of light perpendicular to the train to find how fast the train is moving in the absolute reference frame—on the stationary ground.

Michelson and Morley attempted to make essentially this measurement in the 1880s (on a rotating and orbiting train called Earth), and failed: according to their best measurements, light appeared to propagate at the same velocity in all frames of reference. This indicated either that Maxwell's equations modelling electromagnetism failed here, or that the Galilean transformation modelling velocities in different reference frames failed here.

Many mathematicians and physicists in the late 19th century sought to find a model that matched the Michelson–Morley results as well as prior observations of the Maxwell and Galileo models (which were themselves supported by ample experimental evidence), including Lorentz, Poincaré, and, in 1905, Einstein, who gave the most compelling interpretation (English translation) to date of the mathematical model called the Lorentz transformation. And that is why we have the theory of special relativity today.

Special relativity still had failings, though: The orbit of Mercury was still lopsided in a way that nobody could satisfactorily explain (maybe there was an invisible extra planet out there in the solar system, tentatively named Vulcan; maybe the sun's mass distribution is oblate in a way we can't otherwise see), until the development of the general theory of relativity. General relativity made other remarkable predictions, like the deflection of light around massive bodies which was confirmed by the Eddington expedition in 1919.

So, what are we really using Physics then to do? Making observations?

All models are wrong. But some models are useful.

We can use models of physics to make predictions and decisions—we use predictions from models of physics in engineering to build buildings and vehicles and devices that serve functions, like connecting a machine that burns oil through electrical lines to power your computer screen to read this answer on Stack Exchange.

We use the general theory of relativity to make accurate GPS location measurements from satellites accelerating around the large mass of Earth so that you can find where you got lost on the highway and predict how to drive to the nearest gas station. If a theory of physics didn't work for some purpose, we would stop using it for that purpose and try to find a better theory that does work.

What if I perpetually keep asking "why" to the responses?

Eventually people will grow tired of this kind of childish navel-gazing and talk to someone else, but maybe that's an unpopular opinion on philosophy.SE!

Certainly for some physicists, why they pursue the theories they do is the sheer intellectual stimulation of the pursuit. Why we as a society fund them and support them is that we foresee a possibility of practical benefits as a society from basic research, even if only in the distant future. Why we use certain theories and models for engineering and forecasting is that they empirically match observed reality. But it is futile to ask Nature why she is what she is. We can only model what she is; you'll never hear her say why.

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  • Yes, the Michelson–Morley 'failure' has to be one of the most significant findings in science.
    – Scott Rowe
    Jun 12 at 23:15
  • According to this answer Einstein denied that Michelson-Morley played any significant role in the development of SR, commenting "Ιn my own development Michelson's result had not had a considerable influence. Ι even do not remember if Ι knew of it at all when I wrote my first paper on the subject (1905)." He did however base it on Maxwell's theory of EM which was mostly found empirically, and also perhaps on the empirical success of "Galilean relativity" which says the laws of physics obey the same equations in different inertial frames.
    – Hypnosifl
    Jun 20 at 20:20

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