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Nature Physical Law From Galileo’s Pendulum Xchge

August 14, 2014

  1. 1 Patrice Ayme January 11, 2014 at 03:11

    Equations just depict ideas. Equations can be very hard. Some we have no …idea how to handle them (Navier-Stokes, a most useful equation).

    It’s hard to find new ideas. However, some, once found and accepted, can be amazingly simple. The invention of Non-Euclidean geometry just amounted to admit a pre-Euclidean idea: one could make geometry on a sphere, or a saddle, not just a plane.

    It was more of a philosophical change of perspective than anything else.

    Similarly Einstein took Poincare’s observation that the constancy of the speed of light should be viewed as a physical law, and got the Lorentz group from it. Modulo some mathematics so trivial, Poincare’ had not bother to make them explicit.

    Again a philosophical change of perspective.

    Or Einstein (again) took Planck’s idea of quantified emission of light, and decided that was proof enough that there was such a thing as light quanta Planck disapproved, but that “explained” the photoelectric effect discovered 80 years earlier (Einstein got the Nobel for that simple idea in 1923).

    Philosophical change of perspective, again.

    The discovery of Dark Matter and Dark Energy were as unexpected as that of Quantum Theory. However the Quantum “explained” right away two well-known, yet baffling, experimental facts; the non-occurring “ultraviolet catastrophe”, and the Blackbody Radiation.

    In the present situation, we are not even completely sure that Dark Matter and Dark Energy are really observed facts. The philosophical perspectives, let alone the physical ones, are vast. Breakthroughs will come, first, from simple ideas. Complicated equations will follow.

    We appreciate the brutal beauty of the universe as our judge, because we evolved that way. To find those elements of reality we call the truth. Our glorious survival blossomed that way.

    Science is what we do, as a species. And philosophy is our oracle.

    • 2 Matthew R. Francis January 11, 2014 at 07:03

      What you say sounds reasonable on its face, but there are number of problems with your arguments.

      We use equations in physics because they are effective. The Navier-Stokes equation helps us describe physical phenomena successfully; it doesn’t matter whether you understand it philosophically or not. To cite the most important example of all: people still debate over the proper way to interpret quantum mechanics, but everyone uses the Schrödinger equation and the other mathematical tools because those are the way to do quantum physics. That’s not to say the interpretation isn’t important, but the equations are essential.

      Also, you get the cosmological issues backward. Dark matter and dark energy are observed phenomena (“facts” if you will, though I dislike using that term). “Dark energy” in particular is just the name we give to the observed accelerated expansion of the Universe, for which we currently don’t have a good theoretical explanation. “Dark matter” similarly is the name we give to the simplest explanation for a wide variety of astronomical observations, from the rotation of galaxies to the sound waves in the cosmic microwave background (see the detailed discussion in for more on that second point). These are observations for which we need more theory and observation, not philosophical perspectives.

      Conceptual breakthroughs happen, but they follow hard work. Newton didn’t spontaneously come up with gravity, and Einstein didn’t spontaneously think of relativity. Both of these breakthroughs came after long strenuous efforts, and were built on ideas, experiments, and observations from many others who came before them. When we figure them out, dark energy and dark matter will be no different. After all, we’ve known about dark matter since the 1930s and dark energy since 1998 (with inklings of its existence before then). If all it took was a philosophical perspective, we’d have solved it by now.

      To reiterate, physics is hard, but worth it.

      • 3 Patrice Ayme January 11, 2014 at 12:00

        Dear Matthew: I did not say the Navier-Stokes equation had to be understood “philosophically”. I just alluded to the fact that, although it depicts fluid flow, the general existence and smoothness solutions of this non linear PDE have not been proven (I actually don’t believe they exist).

        Newton did not come up with the gravity law, by the way. He exploited it further.

        The French astronomer Ismaël Boulliau suggested that Kepler was wrong about the gravitational force. Kepler had declared that the gravitational force holding the planets in place decreased inversely to distance. Boulliau held instead that the force decreased as an inverse square law. He deduced this in analogy to light. Isaac Newton acknowledged Boulliau’s discovery.

        Nobody dares to suggest the equations related to Quantum Theory are not essential. To a great extent, they are all what defines the theory. QFT is all about guessing the Laplacian, aka the equation(s).

        The situation with Dark Stuff is not similar. They are not directly observed phenomena (just ask LHC people).

        The “observations” of both Dark Matter and Dark Energy are the fruits of (philosophical) pruning. The former depends, among other things, upon the hypothesis that gravity holds at galactic scales (some employed astronomers claim gravity does not work beyond the Solar System… as seems to be the case, at face value!) It’s hard to evaluate things we don’t know, such as galactic mass (the Milky Way has grown in astronomers’ minds recently) to make further guesses about something else.

        In the case of Super Novae studies, outliers explosions are removed from the sampling. I could not read a clear enough description of what was found (I read the original literature) to see if my pet theory survives.

        Boldly supposing that something is really going on (I know a Nobel was attributed), we are very far from being able to describe the thing (whether, for example it’s a Cosmological Constant or Quintessence field description).

        Physics is what we do, it did not start with Newton. Or Buridan, who discovered inertia, or Aristotle, who got that wrong.

        Physics, finding new physics is desperately hard, but so worth it, our lives depend upon it. They always have.

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