Overdoing Origins

In public controversies over science, there’s a lot of interest in questions concerning the origins of things. Evolution, cosmology, the origin of life—these are considered big questions. I see this in the classroom as well. I like to devote a fair bit of time to questions by students, which can range far beyond what’s in their textbooks. I often get questions about the big bang. This is good; I get to take them on a whirlwind tour of some interesting physics, starting with general relativity. I mess with their concept of time.

But I also wonder. I never get diverted into that sort of discussion because somebody asks me seemingly naive questions that can lead to profound thinking about physics. These are students who haven’t been corrupted by too much physics knowledge yet, so I keep hoping they don’t take too much for granted. Yet nobody asks why the Newtonian gravity equation they first learn is an inverse square law rather than something else. No one asks about whether we can have negative mass. They just take F=GmM/r2 as a formula to use in solving some idiot problems, no questions asked. It’s only when they get curious about the big bang—something about origins—that they give me the opportunity to shake things up.

So I have to ask if this is mainly an artifact of our intellectual culture, linked perhaps with theistic religious habits, that puts so much emphasis on “origins” questions. We seem to have the prejudice that if we sort out the events of creation—of the universe, of humans as a species, and so forth—that gives us some profound knowledge of what is to follow. Origin stories determine the important features of what we have today. God infuses his holy purpose into his creation as he creates it: all that matters is foreshadowed from the Beginning. Even if we start doubting the gods, secular echoes of the sacred Time of the Ancestors remain with us.

I shouldn’t complain about whatever excuse I get to talk about interesting science. But I also worry that emphasizing origins distorts our understanding of science. It certainly isn’t true to the physics. There are vast amounts of profoundly important physics that have little to do with the cosmology of the early universe. And it simply isn’t true that if you understand the big bang, you automatically know the important features of our universe, 13.7 billion years after the fact.

Intellectual nonbelief today is unavoidable deeply colored by its recent history, dominated by an oppositional stance. I suspect that if we were to achieve a truly post-theistic culture, things would be different. Physical cosmology would be a perfectly respectable and exciting subdiscipline of physics, but it would have less of an aura of Significance. Evolution would remain key to understanding life, but perhaps be less entangled in conceptions of a human nature fixed once-and-for-all by its origins. Maybe we would realize better that we live in the here and now if we did not feel compelled to ask how we fit into an Original Drama, with a script written by the gods in a sacred past.

About Taner Edis

Professor of physics at Truman State University

  • http://www.blogger.com/profile/00565212411446092552 smijer

    So, why is it an inverse square law? I remember wondering about that myself, recently, but I just shrugged & decided that it had something to do with geometry… Is there a better answer that you know?

  • http://www.blogger.com/profile/03034292023591747601 PersonalFailure

    can we have negative mass?

  • http://www.blogger.com/profile/02804655739574694901 Andrew Shields

    This made me think of Nietzschean genealogy: Nietzsche argues that the original intention or condition of any given feature of our world does not have any necessary connection to the contemporary appearance of that feature. (His example is morality; yours is the universe.) That his genealogy is against teleology is patently obvious; that it is against “originality,” so to speak, is harder to keep in mind.

    Or to put it another way: etymology does not really tell us much about how a given word is currently used. But people constantly act as if it does.

  • http://www.blogger.com/profile/11399828220100913111 UnBeguiled

    For most of my life I found the inverse square law spooky. So gravity falls off with the square of the distance. And so does magnetism. Why should that be?

    Then I leaned it was a natural outcome of existing in 3 dimensional space. Cool. I think I learned that from Sagan. I’m pretty much a physics cretin though. I don’t really understand anything.

  • http://www.blogger.com/profile/12708768497461983779 nolandda

    I suspect the interest in origins has more to do with our natural tendency to communicate and reason by use of narratives. How the story begins is a critical part of any narrative.

    Therefore I think origins would still carry an aura of significance even in a post-theistic world.

  • http://www.blogger.com/profile/10778996187937943820 Taner Edis

    Yes, the inverse square law is a consequence of geometry. It’s because we live in a 3D space.

    If a force is mediated by a particle that has no rest mass, does not strongly couple to itself, has no lower energy states it can easily decay to, and space is reasonably flat, you’ll get an inverse square law. The intensity of particles will fall off with the square of the distance from the source. Think of a sphere. Its area goes like the radius squared, and you distribute the same number of particles over an increasing area.

    Photons are like that, and so electrostatic forces fall off like an inverse square. For gravity, gravitons would be the particles in question. But then again, we don’t have a full theory of quantum gravity yet, so gravitons have some question marks hanging over them.

    There’s no evidence for negative mass. If we had it, it would be thoroughly weird. You’d push on a negative mass object and it would accelerate in the opposite direction. Causality and a bunch of important physical symmetries would be shot. But you’d be able to construct macroscopic wormholes and make warp drives.

  • http://www.blogger.com/profile/11399828220100913111 UnBeguiled

    Thanks Taner. So a force diminishes inversely to the square of the distance for the same reason the surface area of a sphere increases with the square of the radius. It seems so obvious now. Thanks for explaining that.

  • http://www.blogger.com/profile/09925591703967774000 Dianelos Georgoudis

    I suppose to say “origin of X” is a fancy way of saying “explanation of X”, and I see nothing wrong with people trying to explain things to an ever deeper level. On the other hand I find it entirely reasonable to assume that it’s not like “turtles all the way down” and that there is therefore one or a number of ultimate explanations that do not admit of further explaining. In other words I think it’s entirely reasonable to assume a rock bottom level to reality. In this sense I think that both theists and naturalists are entirely within their epistemic rights to make a few irreducible claims about initial origins, or uncaused causes, or the existence of an explanans that is not an explandum. The relevant question is this: Given this set of uncaused causes, how good an explanation of the whole of our experience of life results from it?

  • http://www.blogger.com/profile/02804655739574694901 Andrew Shields

    Dianelos, isn’t the point that “origin” does not always equal “explanation”? Etymology is a good example, as I mentioned.

  • http://www.blogger.com/profile/06056410184615941086 M. Tully

    “They just take F=GmM/r2 as a formula to use in solving some idiot problems, no questions asked. It’s only when they get curious about the big bang—something about origins—that they give me the opportunity to shake things up.”

    Well, the fact that they accept empirically proven equations is (unfortunately) because memorizing equations has gotten them successful test scores.

    Having said that, what’s wrong with giving them credit for accepting equations that make verifiable testable predictions about the world around them?

    Then feel free to inquire about why they answered the way that they did. “Have you ever personally tested this prediction yourself? Well then maybe we should.” “Why didn’t the results come out EXACTLY as predicted?” What a great teaching moment!

    As far as origins are concerned, what a fantastic way to teach about the edge of science.

    The most important lesson I ever learned…

    …It is O.K. to say, “I don’t know.” And even better to say that, “I really want to find out!”

  • http://www.blogger.com/profile/10778996187937943820 Taner Edis

    M. Tully: “what’s wrong with giving them credit for accepting equations that make verifiable testable predictions about the world around them?”Nothing’s wrong with that. And they get plenty of credit. It’s just that (like everyone who teaches, no doubt), I wish I occasionally got more of the more penetrating sort of questions.


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