Revelations and Rules of Thumb
© 16 Mar 2014 Luther Tychonievich
Licensed under Creative Commons: CC BY-NC-ND 3.0
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On faith, trust, knowledge, and the straw man fallacy.


I have tried several times to find a nice tie-in to make the end of this post feel like a conclusion. I failed; it just sort of stops instead. You have been warned.


I played my first game of golf fairly late in life. After a few rather sad swings, I was given a simple rule of thumb: follow through on your swing. Now, I had, at this point, taken almost two years of university physics. I had tutored people in the subject. I had gone farther: I had taught computers how to model physics, including the physics of golf. I knew about impact, recoil, vibration, spin, fluid friction, lift, drag; I could even make educated generalizations about quantum wave interactions. All of these confirmed one immutable truth: within a millisecond after contact, there was no causal link between what my club did and what the ball did. No part of follow-through could possibly impact the ball’s flight.

On my next swing, I followed through, bringing my club all the way around up over my head and on until it was horizontal past my back. The ball went much straighter and farther than ever before.

I know—I have absolutely no doubt at all on this point—that following through on a golf swing has no influence on the ball at all. I also have strong evidence that it does have it does influence the ball. Rationally, there must be an intermediate force: presumably my intention to follow through changes the downswing.

Rule of Thumb

I have many dictionaries. I like dictionaries. The following definition of “‍rule of thumb‍” shows up verbatim in three of mine: “‍a rough, practical method of procedure.‍”

Science tells us how the world works. Rules of thumb tell us how to work within the world. Rules of thumb are more useful day to day than science because they are practical methods, they help us proceed. We generally know they are not “‍correct‍” in any rigorous sense, but they work.

I believe in rules of thumb, and I believe in science. These kinds of belief share a lot in common: I know they work, that what they say is true within it scope. I know that each rule and each theory is limited in scope, that they do not describe everything perfectly. I know they are incomplete and that a better rule or theory might come along. I know that applying several rules or several theories at once poses challenges because their interactions can be hard to predict.

Those similarities notwithstanding, my belief in each is distinct in kind. I believe the rules of thumb work, but I don’t necessarily believe they are true. I believe the theories are true, but I don’t necessarily believe they can help me act wisely. Schrödinger’s equation may describe the entire universe Except not big things moving quickly, which basically means it doesn’t describe the universe at all… which is to be expected from an analogy. but it gives no useful information when it comes to making almost any kind of decision.

Learning False Things

One more idea should be added to this distinction between theory and practice, between laws of nature and rules of thumb. We almost always teach the wrong one first.

My friend Eric has taught his children the following simple rule of thumb: play with toys, not with tools. But that’s not really the rule of thumb Eric uses; he operates under a much more sophisticated set of rules about using each thing within the scope of its purpose. It’s just an approximation of the rule, a simpler version to teach first.

The same thing is true on the theory side. I’m guessing most of my readers have still not been introduced to the “‍true‍” theories scientists use today any more than the know the nuanced rules of thumb used by skilled practitioners of any trade other than their own. There is a practical and theoretical reason for this: you can’t go from ignorance to nuanced understanding without passing through some kind of intermediate step, and that intermediate step needs to make sense, it needs to be able to stand on its own, even though it is at least incomplete and often simply false.

To learn means to learn false things before you get to the true.


Consider, now, matters of faith, by which I mean to suggest “‍faith in‍” and “‍faithful‍” and “‍various faiths‍”. In other words, consider religious belief.

If we grant that there is divine power teaching mortals about divinity, should we not expect that mortals first learn the preliminary rules and theories? And since divinity appears beyond the reach of at least the vast majority of mortals, shouldn’t we expect to see one pre-truth replaced with another with few if any humans seeing the final truth?

Anyone can find a flaw in the teachings they’ve seen by the mid-point of their course of study. They are teachings, waypoints on the road to truth. They are meant to hold together well enough to help you reach the next waypoint. Far too often people attack rules of thumb as if they were theorems, or set up a straw man based on an intermediate view of a doctrine and then show that that intermediate understanding is false. Indeed, I almost never hear any belief system, in religion, philosophy, science, or anywhere else attacked in any other way.

Even believers are often confused by this. How easy it is to think a good rule is a theorem! We can so easily jump from “‍follow through‍” to “‍the ball reacts to how you move the club after you hit it‍”. I am amazed how often I see this, even in myself. We so love to look beyond the mark.

And so we come at last to a rule of thumb I find useful when I am inspecting my own faith: Trust the rules, believe the teachings, put your faith in God; accept your current understanding but expect it to be refined.

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