The Head and the Hands

The other day I received a review on one of my manuscripts that said that this MS was not acceptable (for some journal, not ours) because I was a theoretician whereas the MS merely described (theoretically unmotivated) empirical data. Since the editor told me he concurred with the reviewer's verdict, I trashed the MS. I have published a few purely theoretical papers in my timeönothing wrong with the reviewer's memory. However, I have always admired people who manage to `̀ think with their hands'' and pursue purely empirical research in an intelligent manner. I like to fancy that I'm able to do so myself, and I resent being pigeonholed a `theoretician'. When discussing this experience with friends I noticed that the topic of data-driven versus theory-driven research is a very interesting and indeed basic one. People apparently hold strong opinions on it. It is understood by many that the `scientific method' (SM? ) implies that one entertains theoretical predictions and devises experiments in order to falsify these. I must confess that (after decades of scientific practice) I haven't been able to pick up the correct scientific method. It was not taught in any classes I attended as a youngster, and, though I picked up all I know through hands-on laboratory practice, none of my heroes (in retrospect) seems to have held a clear notion of the scientific method either. The people I admired most approached their research in a very common-sense, almost ruthless way. No holds barred, only the result counts. If one discovers something by accident, that is nothing to be ashamed of. If one is at a loss to proceed, one simply tries something, often for no good reason, without getting red in the face. One is always ready to catch fortune when it passes by. On the other side, theories are fun, whether they fit the facts or not. In fact, one rarely expects (interesting) theories to fit the facts exactly. A theory is much more interesting when it fits a large class of phenomena approximately, or qualitatively, than when it fits a very limited class of phenomena very precisely. All such convictions seem to run against the grain of `officially' acceptable scientific practice. Many of my students appear to understand the scientific method much better than I do. They are often worried when I advise them to try something for no explicit reasons and they will spend ages thinking over problems on which current theory has little to say. I try to convince them of the sanity of common sense. If you haven't the faintest notion of what is behind a door, what should you do? Of course, you might come up with many fancy theories. If it turned out to be a closet door, you might expect a skeleton; if there's a hallway behind it, perhaps a butler keen to overhear our conversation, in a surreal movie you might expect a desert scene, and so on and so forth. My advice is to perhaps stop theorising for a moment and simply to open the door and take a look. Students are scandalised by that very idea. To pursue empirical studies for their own sake (`butterfly collecting') is simply bad form. At least for the True Scientist. Conversely, I have nothing against the pursuit of theory for its own sake. I enjoy doing so myself. I believe the theoretician shouldn't be fettered by what are currently believed to be the empirical facts. When the theory really fits the facts, both must be boring (and be probably wrong) anyway. There exist many trivial tricks to make a theory fit the facts that are little better than cosmetic.Why bother? The mark of a good theory is not at all that it fits the facts exactly, but that it is robust and is fruitful in its consequences. Guest editorial Perception, 2002, volume 31, pages 517 ^ 520