Rule no. 1 is iterative, recursive, and reflexive. It applies to all explanations and rules, including itself.
I have no doubt that in reality the future will be vastly more surprising than anything I can imagine. Now my own suspicion is that the Universe is not only queerer than we suppose, but queerer than we can suppose.
–J. B. S. Haldane, Possible Worlds and Other Papers (1927), p. 286
It isn’t hard to see that that’s the case. The mass of a human brain is a kilogram or so; the mass of the Universe is currently estimated at around 1052 kilos. To suppose that any large fraction of the state of the Universe could be encoded into such a small object is foolishness.
What we can do is arrive at approximations that are sufficiently accurate to get on with. Newton’s laws are almost trivially simple (yes, yes, I hear you groaning in the background; EngLit major, I take it? But they are) and are completely superseded by Einstein’s and later work, but for ordinary, everyday experience they more than suffice to figure out what’s going on, and to predict results in the physical sense. You don’t need the Lorentz Equation to figure out where a baseball (or an artillery shell) is going to go, and you don’t need to solve tensor equations to work out whether or not being hit by a truck is going to hurt, or how badly; Newton is enough, if not excess to requirements. Even the people who manage space shots and satellites don’t have to worry about the difference between Newtonian predictions and the more accurate Einsteinian analysis until they get to the fourth or fifth decimal place. Of course, when you start working in millions or billions of anything, as the space wallahs must all the time, the fourth or fifth decimal place can mean the difference between hit or miss.
So any time you come across a Law, a Rule, or an Explanation, keep firmly in mind that it isn’t complete, and that the differences, exceptions, and erroneous bits can lead you widely astray.
There is an exception, of sorts. Those of us who are believers tend to explain things using the form “God did it”. That is, in fact, a complete explanation; the problem is, it isn’t useful. We are looking for ways to push the Universe around for our benefit. Newton’s Laws give us a clue as to how to do that. “God did it” is not something we can emulate, even at the lower and/or simpler levels, because there are no lower or simpler levels.
Rule #1 is iterative, because no matter how much additional material you add to the explanation it is still not complete. The Rule is recursive, because no matter how hard you try to pin down the meaning of the individual parts of the explanation you haven’t achieved completion. And the Rule is reflexive, because it applies to itself — compound complexity in an explanation is not a positive, it’s one of the grosser forms of oversimplification. “We can’t handle this, it’s too complicated” is a cop-out, and when someone offers an explanation that’s opaque or obfuscatory in its complexity, you can generally expect that they’re trying to get you to accept something that isn’t useful (“baffle ’em with bullshit”).
None of this is to say that you should just give up. Ordinary simple explanations and rules suffice for a huge part of our daily experience, and only slightly more complex ones cover all but the most extraordinary cases. The purpose of rules and explanations is to give us guidance about how to accomplish things, and if the ones you use manage that, they are sufficiently complete to be useful; and that’s all anyone can ask.
It’s just that, no matter how apparently satisfying or useful the rule may be, you should always be aware that it’s incomplete, limited in application, and subject to exceptions. Seizing upon a Rule, and insisting that it applies in all cases, is the essence of fanaticism. In fact, the only Rule I know of that has no exceptions is this: All Rules have exceptions.