Construction of a Theory

Here’s an incredibly economical depiction of the relationship between evidence, experiment and theory swiped from Three Quarks Daily. It shows both the process and the uncertainty. It’s a little on the long side, so I’m placing it below the fold.

One aspect that this doesn’t cover is the usefulness of a theory. Theories are used to make predictions that can be tested. Those tests are themselves experiments.

To follow the analogy, we’d use the pentagon shape figure out where a point that we haven’t yet discovered might lie. We look there and try to find a point. If it’s there, our confidence in the theory is strengthened. If it isn’t, we go back several steps, fiddle with the drawing and try again. (As Kuhn pointed out, it isn’t quite that simple, but close enough for this example.)

Isaac Asimov once used the analogy of constructing a map using points of latitude and longitude. The advantage of this analogy is that you can immediately see how to make useful predictions with a map. Figure our where you want to go and try driving there. If you wind up in the middle of the ocean, you know your map is inaccurate. Make corrections and try again.

The question arises: is the map the terrain? Or in other words, is the theory a perfectly accurate depiction of the reality? The pure answer is: of course not. The pragmatic answer is: who cares?! As long as the map gets you to where you want to go, it’s good enough.

  • Elemenope

    And everyone gladly sopped up all the scientist’s great theories, until that fateful day when the last point of data ruined all their pretty pictures of the perfect square they knew, in their hearts, the truth to be.

    • David Evans

      Indeed. As any theologian could have told them, it is a capital mistake to collect more data than you need.

  • UrsaMinor

    Overall, I like it. But sadly, this example rather sloppily conflates hypothesis with theory. I realize that it’s meant to be a simple teaching tool, but this is a very important distinction on which the public needs to be educated, too.

    • Elemenope

      Not to mention that the first data point can never be considered “evidence”, because there is no hypothesis for it to be evidence of. It is merely an observation, and if it manages to stimulate the formation of a hypothesis it might even be an anomalous observation; lofty to be sure, but not evidence.

      Science in the broadest strokes is very easy to understand; take an idea, test it repeatedly, see if it survives. Keep what survives, discard the rest. Take what you’ve kept, use it to predict what you’ll see next. What you see next may give you an idea…

      It’s where the rubber hits the road that all the neat explanations fall apart. When one starts asking questions like: what does it mean to hypothesize? What is an observation? How do scientists actually do science (as a practice)? …these explanations become about as convoluted and unsatisfying as the Trinity. At least, at the very least, when scientists and philosophers of science run into these uncomfortable questions, they don’t succumb to the “making-shit-up-so-it’ll-all-fit” instinct.

  • Reginald Selkirk

    There’s a few steps missing:
    So we tend to focus on the theory with the fewest assumptions
    .
    Hmmm. If there are multiple theories in contention, a good scientist will design the experiment so that it produces data which will help to distinguish among the candidate theories. This is one of the problems with experiments concerning “alternative” medicine, to name just one example. If all of the resulting papers end with “more research is needed,” then you really haven’t advanced out knowledge.

  • Kodie

    While I agree with the criticisms of this piece, it sure makes it intimidating to try to correct someone or have a discussion if you might be explaining it wrong or switching the terms. I have some confidence that I understand concepts much better than I can explain them to someone else. I think it’s good that someone gets the big picture, you know, if you post it on the internet, the real nerds will (and I mean that lovingly, not disparagingly) come along to fine-tune it in the comments. I don’t want to feel too self-conscious about getting something mostly right, or at least in, like vorjack said, economical diagram that… perhaps “dumbs it down” for a dummy like myself, or people with a radically different viewpoint try to grasp something difficult like science, that can be too broad and complex to them that they simply cling to what they do know to avoid feeling overwhelmed by how much they don’t know, or how to start to know it. Unlike a lot of people here, I have no academic background in sciences. Once I can understand something, I will still get it wrong if I try to explain it to someone who doesn’t understand it. You have to start somewhere.

  • vasaroti

    There was a chat on NPR recently about the value of “fishing expedition” research which is not hypothesis based. Made sense to me. Without a :fishing expedition” one might not discover that “the truth” was a circle, not a pentagon.


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