How Do We Know the Laws of Physics Will Persist?

Lynne Kiesling

I’m not going to go off on a Schroedinger’s cat tangent or anything, but there’s a really neat article in today’s New York Times about the laws of physics. In a nutshell, here’s the dilemma: how do we know that the laws of physics are true? Can we prove their truth in an overall, universal sense, in the sense that explains the order observed in the universe?

This is an interesting question. Think about it: you go about your daily activities assuming that gravity and surface tension and fluid dynamics and all of the other physical relationships that allow you not to dissolve into a puddle of bodily fluids are true. But what’s interesting is that you can’t prove deductively that they are true. Sure, you can falsify all sorts of alternatives, and the relationships that we call the laws of physics are the last ones standing.

Are they merely fancy bookkeeping, a way of organizing facts about the world? Do they govern nature or just describe it? And does it matter that we don’t know and that most scientists don’t seem to know or care where they come from?

Apparently it does matter, judging from the reaction to a recent article by Paul Davies, a cosmologist at Arizona State University and author of popular science books, on the Op-Ed page of The New York Times.

Dr. Davies asserted in the article that science, not unlike religion, rested on faith, not in God but in the idea of an orderly universe. Without that presumption a scientist could not function. His argument provoked an avalanche of blog commentary, articles on Edge.org and letters to The Times, pointing out that the order we perceive in nature has been explored and tested for more than 2,000 years by observation and experimentation. That order is precisely the hypothesis that the scientific enterprise is engaged in testing. …

There is in fact a kind of chicken-and-egg problem with the universe and its laws. Which “came” first — the laws or the universe?

The article then goes on to discuss Plato’s concepts of ideal forms and the laws of physics as an instantiation of those concepts. But we can’t escape the fundamental problem that we are trying to analyze a large, complex system from within that system, and that because of that, we have to assume the orderliness of the system as a fixed point, if you will, in the argument in order to be able to make any progress in understanding the system to the extent that we can.

Fascinating. A very thought-provoking read.


5 thoughts on “How Do We Know the Laws of Physics Will Persist?

  1. I haven’t read the original Davies op-ed — and what kind of an organization is the New York Times running when they publish online a story referring to an earlier item published in their own damn newspaper and they don’t include a link — but it seems like Davies is just playing on multiple meanings of words like “faith” to try to claim some sort of “gotcha” against science.

    The thing is, we don’t really have to “assume the orderliness of the system” so much as to simply believe the evidence of our senses. The evidence of our senses tends to suggest that the system is orderly. When it turns out that the evidence of our senses goes wrong, as it often does, the response is to collect more evidence and to do it more carefully.

    Science is ultimately pragmatic, interested in discovering what works. Belief in orderliness of the system usually works, and when it fails, the response is to revise ideas about the system until it appears orderly again.

    Religion is similarly about “what works” in a sense, but when religious belief doesn’t work it usually prompts a different response than when a science belief doesn’t work.

    I guess I fall into the “faith” described in the article by Steven Weinstein — “the phrase “law of nature” [is] “a kind of honorific” bestowed on principles that seem suitably general, useful and deep. How general and deep the laws really are, he said, is partly up to nature and partly up to us, since we are the ones who have to use them.”

  2. One thing Davies is saying, without putting it this way, is that there exist axioms upon which all of our findings rest. This reminds me a bit of the mathematicians who are searching for an axiom-free algebra, a system of mathematics that can prove its own existence without any exogeneities.

    This whole thing reminds me a bit of Hayek’s concept of the fatal conciet. Not with respect to socialism or anything, but the idea that as organisms in a system, we are limited in what we can know (and thus, what we can do) about that system, and any attempt to divine a fuindamental understanding of the nature of reality necessarily requires a frame of reference – ours. We cannot describe reality without looking at it from where we are, and the simple act of having to stand somewhere to observe inherently jaundices the interpretation.

    I agree with Mike, science may be based upon certain (at present) untestable hypotheses that could be called “faiths”, but the fact is, when tests are devised and hypotheses invalidated, then science reacts differently to religion. However, by its very nature, science is about falsification, not verification, so it can never be a religion, because religions are about providing truths, and not just rejecting falsehoods.

  3. Yes, yes, you both have hit on precisely my point. I’ll take it a step further: at its core, this is the inductive root of science. We can only infer order from the evidence of our senses by using induction (yes, in conjunction with deduction, but just go with me here …). We observe over time that outcomes are consistent with order. That’s an inductive process. We don’t deduce the causes of order from first principles; we can’t, because we can’t falsify the hypotheses that would arise from the deduction.

    Just wanted to put the dot on the exclamation point to reinforce my bust on the Cartesian mindset …

  4. I would massage Barry’s words a bit, to say that we cannot know if we describe our reality accurately unless we can position ourselves outside the system. Obviously we can’t do that because we are part of the system. That we can view the system only from within means that some things about the system are unknowable.

    But this seems little different from mathematics, which can be twisted into Gödelian knots that are undecidable. So it really should no longer be news that knowledge is limited in many/most/all ways when dragged into self-referential loops. Hayek knew it. Gödel knew it. And good’ole Hofstadter described it in the mass media long ago (which is probably the only reason I think I know anything about it). It’s the malleable substrate of our existence, and science, religion, economics… you name it… rests atop. But we (humans) don’t resort to these epistemological limits often because it’s not all that fruitful or practical. We can establish hypotheses about reality as we see it, test these hypotheses, and build an incredibly complex system of relationships that seem to work. On those we build economic activity, which is the advanced complex human system of life that lifts us above hand-to-mouth subsistence. It’s fascinating that the foundations aren’t really concrete, but it’s not a practical concern… to an engineer. 😉

  5. I would massage Barry’s words a bit, to say that we cannot know if we describe our reality accurately unless we can position ourselves outside the system. Obviously we can’t do that because we are part of the system. That we can view the system only from within means that some things about the system are unknowable.

    But this seems little different from mathematics, which can be twisted into Gödelian knots that are undecidable. So it really should no longer be news that knowledge is limited in many/most/all ways when dragged into self-referential loops. Hayek knew it. Gödel knew it. And good’ole Hofstadter described it in the mass media long ago (which is probably the only reason I think I know anything about it). It’s the malleable substrate of our existence, and science, religion, economics… you name it… rests atop. But we (humans) don’t resort to these epistemological limits often because it’s not all that fruitful or practical. We can establish hypotheses about reality as we see it, test these hypotheses, and build an incredibly complex system of relationships that seem to work. On those we build economic activity, which is the advanced complex human system of life that lifts us above hand-to-mouth subsistence. It’s fascinating that the foundations aren’t really concrete, but it’s not a practical concern… to an engineer. 😉

Comments are closed.