The Uses Of Simplicity

     These days there’s quite a lot of “loose talk” about “tight stuff:” that is, talk about concepts that have precise meanings and shouldn’t be batted about in a careless fashion. Some such concepts are among the most useful ideas men have ever produced...but their utility depends upon precise comprehension. If you don’t understand it as it’s meant to be understood, you won’t use it as it’s meant to be used.

     The field of heuristics incorporates several such concepts. If the term heuristics is unfamiliar to you, it’s the “applied” side of epistemology: the branch of philosophy that addresses what we think we know and how we came to believe it. Heuristics is the grab-bag into which we toss our techniques for solving problems and extending our knowledge.

     People frequently employ heuristics without knowing that they’re doing so. Of course! Any practical technique for learning something qualifies as a heuristic, so any method by which we approach a problem qualifies, informally at least, as a heuristic. If it works, that is!

     Probably the “best known” heuristic technique – those are sarcasm-quotes, not scare quotes – goes by the name of Occam’s Razor. It supposedly originated with William of Occam, a Fourteenth Century English friar, philosopher, and theologian. The “traditional” statement of his Razor was simple and evocative:

“Entities must not be multiplied beyond necessity.”

     Isn’t that an “of course” sort of statement? We don’t put unnecessary ingredients into our recipes or unnecessary parts on our machines. So why is this statement regarded as such an important breakthrough in thought?

     Well, in point of fact, the “traditional” statement says very little. It’s the way that principle is used as a heuristic – i.e., how it’s applied to problem-solving – that makes it valuable. In the problem-solving domain, most particularly the problem of explaining an observable phenomenon, it works this way:

1. Gather as much information about the phenomenon and its context as possible.
2. Now eliminate from the context all but one feature: the one that seems most likely to “produce” the phenomenon. Create a “test environment” containing only that feature.
3. TEST! Does the phenomenon occur in the test environment?
   • If so, you have a workable temporary explanation for the phenomenon.
   • If not:
     1. Add another, plausibly related feature to your test environment;
     2. Return to step 3 (TEST!) above.

     The question the student new to Occam’s Razor will normally ask at this point is “But why? Why use that procedure?” And he is right to ask.

     The reason is supremely practical: The fewer elements there are in any proposed explanation for a phenomenon, the easier it will be to test. Therefore, we’ll finish soonest if we use that order to winnow through the possible explanations.

     Note: That’s not the same as the “vulgar” statement of Occam’s Razor – i.e., that “the simplest explanation is most likely to be correct.” That is quite literally nonsense.

     Consider the following, seemingly simple situation: I have in my hand a steel ball. I stand, hold the ball out at a height of four feet, and open my hand. The ball falls. Half a second later it hits the floor. Why?

     Of course you know the answer: Gravity! Plus simple kinematics, of course. Distance traveled from a standing start under constant acceleration equals 0.5*a*t^2, right? Right! But wait just a moleskin-gloved minute there, Colonel: What’s producing that “gravity?” The ball itself? Would we get the same results if instead of a steel ball, we dropped a ball of feathers? Suppose we tried our test outside, in the wind? What then? And how about under water, or in interplanetary space?

     It develops that there are several other elements necessary to the context: elements we omitted to include in our summary of the experiment. The seeming simplicity of our original explanation was premised on an assumption: a solid object of high enough mass density to be negligibly affected by air resistance and air currents, dropped from four feet above the surface of the Earth. It’s the mass of the Earth that produces the local gravity vector. Galileo wouldn’t have got the same results under water, or on the Moon. (Fortunately, the crowd watching his famous experiment didn’t think to suggest those venues.)

     The simplest explanation – “That’s just what balls do when dropped four feet” – was incorrect. So would be any other explanation that omitted the size, shape, and density of the ball, the presence or absence of resistive media and currents within it, or the proximity of a spherical mass of 6*10²¹ tons with a diameter of approximately 7900 miles. It all counts.

     Were we utterly ignorant of the laws of gravitational attraction and determined to figure out why a steel ball dropped four feet takes half a second to hit the floor, it would be smart to test the simplest explanations first, not because they’re “likely to be correct,” but because we’ll eliminate wrong answers fastest that way.

     If you’re guilty of having misunderstood Occam’s Razor before this, don’t feel too bad. Lots of very bright people, including a number who have reason to know better, have misstated it and misused it to promote their preferred explanations for various things as “the most likely.” Some of them had axes to grind. Indeed, whenever you hear someone proclaiming a thesis that “can’t be wrong,” you’re not listening to reasoning, but to propaganda.

     The “global warming” crowd is especially culpable in this regard. Much of the time they don’t even bother with observable phenomena, but restrict themselves to simulations of nonexistent conditions and then claim that “this is what’s happening to the Earth.” When they do address observed phenomena, they almost never include all the relevant conditions in their proposed explanations of events – but they always claim they need more money and power. Were we to apply Occam’s Razor in their fashion to their behavior, we would surely conclude that the simplest explanation – i.e., that they want more money and power regardless of what the climate of the Earth is doing and why – is the most likely to be correct. And upon that note I retire from the field.