Classifying the classics

There is a very small number of scientific papers that are agreed-upon classics.

I won’t stir much controversy to suggest as examples Shannon’s papers on information theory, Turing’s paper on computation, and Einstein’s papers on relativity.

Further down the totem pole, every subfield of science has its own classics. One subfield I work in – quantum information science – has Feynman ’82, Deutsch ’85, Bennett et al ’93, Shor ’94, and so on.

Among the crowd of people who work in the field, not only are journal references redundant in that list, the list itself is almost redundant. Everybody in the field already knows what the classics are, and would probably write down much the same list, albeit in a rather more complete fashion.

I’m curious as to what makes a paper a classic, and if there are broad classes of classic papers.

One thing I find really striking is that many classic papers do not smash really difficult problems. In physics – both theoretical and experimental – the stereotype of a major advance is the solution to some long-standing problem. Yet only a few of those classic papers solve a long-standing problem.

So what do those other papers have that give them classic status?

I’ll come back to this question in more detail at some later time. For now, a short answer.

In at least some instances, classic status is accorded a paper that identifies a hitherto unknown motivating context – a big story you can tell about why some set of big questions is interesting. The paper might ask some interesting new “big” questions itself, or set some old questions in a new context that makes it apparent why those questions are interesting. Furthermore, the paper will suggest a framework for making progress on those questions, often by introducing new definitions, and making some minor technical advances.

For example, in 1985 Deutsch introduced his model of a quantum computer, and showed how to solve a simple problem in that model. Technically, this was not difficult. But it showed people a way to make further technical progress, progress that resulted in Shor’s famous 1994 paper on fast factoring with a quantum computer.