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Keeping it Simple — 2 Comments

  1. I think I follow what you mean, for the most part. However, isn’t it the case that, while simpler explanations are better, things in science are always very complex? A human body doesn’t run because of one simple reason, like “It runs because of Life Force.” It runs because of tons of different things happening, like breathing, blood moving, eating, etc. So isn’t the more complex answer here the correct one, while the simpler answer is incorrect?

    • It’s certainly true that a complex answer is often correct and a simpler answer not. And so evidence often drives us from simpler to more complex explanations. The evidence (e.g., of the fact that we’re thinking about this) shows us that the simplest hypotheses (nothing exists) is not true. Some things (like us) exist. The evidence also shows us that Parmenides’ claim is false; there is more than one thing; there are a great, great many of distinct things.
      But when we’re choosing between explanations which fit the evidence equally well, the simpler explanation is always better than a more complex one.
      It fact, physicists seem to be confirming Leibniz’s claim that the world exhibits a balance of simplicity of principles (laws of nature) but a variety of effects. (Leibniz argued that God was trying to maximize both these factors in the way He created the world.)
      Anyway, when choosing between hypotheses that fit the evidence equally well, the simpler hypotheses are always better.
      I should clarify that ‘fit’ should be taken broadly and strongly here: it isn’t just that the explanatory hypothesis must be *consistent* with the evidence. It must also actually *explain* it. To explain at all, the supposed truth of a hypothesis must make the evidence more-to-be-expected than supposing the hypothesis is false. And the more the evidence is expected assuming the truth of the hypothesis, the better explanation the hypothesis provides of that evidence.
      So simplicity isn’t the only factor in choosing between explanatory hypotheses. Also important is how strong an explanation the hypothesis provides (as explained above).
      But among explanatory hypotheses that fit (including explain) a body of evidence equally well. The simplest is always best.

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