Heuristics

As usual, I'll start with the dictionary definition, although I find it a bit opaque.

Of or relating to a usually speculative formulation serving as a guide in the investigation or solution of a problem: “the historian discovers the past by the judicious use of such a heuristic device as the ‘ideal type’ ” (Karl J. Weintraub).

The etymology is a bit more transparent.

< Gk. heuriskein, to find.

I found an even clearer explanation in How to Solve It, which is an entire book about heuristic methods in mathematics.

Heuristic, or heuretic, or “ars inveniendi” was the name of a certain branch of study, not very clearly circumscribed, belonging to logic, or to philosophy, or to psychology, often outlined, seldom presented in detail, and as good as forgotten today. The aim of heuristic is to study the methods and rules of discovery and invention.

:

Heuristic reasoning is reasoning not regarded as final and strict but as provisional and plausible only, whose purpose is to discover the solution of the present problem. We are often obliged to use heuristic reasoning. We shall attain complete certainty when we shall have obtained the complete solution, but before obtaining certainty we must often be satisfied with a more or less plausible guess.

In that last sentence, you can see the “rule of thumb” aspect I'd picked up on.

I haven't read the whole book yet, just peeked around, but in my peeking I did find one other nice thing.

Bolzano, Bernard (1781–1848), logician and mathematician, devoted an extensive part of his comprehensive presentation of logic, Wissenschaftslehre, to the subject of heuristic (vol. 3, pp. 293–575). He writes about this part of his work: “I do not think at all that I am able to present here any procedure of investigation that was not perceived long ago by all men of talent; and I do not promise at all that you can find here anything quite new of this kind. But I shall take pains to state in clear words the rules and ways of investigation which are followed by all able men, who in most cases are not even conscious of following them. Although I am free from the illusion that I shall fully succeed even in doing this, I still hope that the little that is presented here may please some people and have some application afterwards.”

I like this passage for several reasons, not least because it reminds me of me (see Hume's Funeral Oration). Specifically, it reminds me of one of the goals of urticator.net, the idea of collecting good ideas from all sources while acknowledging that there's nothing new under the sun … not even the idea of collecting good ideas, apparently.

I also like the part about people not being conscious of the rules they follow, because it struck me as so clearly being a statement about memes, although of course Bolzano wouldn't have put it that way. It also forced me to make the productive association between memes and rules, which I'd somehow managed to avoid in the past, even though it's apparent in the fragment from Snow Crash I quoted in Do Words Control Thought?.