Asymmetries in scientific fields

I’ve just finished reading Michelle’s candidacy report, on some of the research she’s been doing into catalysts for certain reactions in organic chemistry. It’s highlighted for me some of the differences between different fields of research — and in particular, between theoretical physics, and the more experimental work that most other people at Caltech do.

Michelle’s report was very easy to read. That’s partially because it’s well written, but I’d say it’s also because the difficulty is in a different place to that of papers that I’m used to reading. “Reading” a longish string theory paper can take literally months — and even then, I can’t claim to understand everything that is being said. Reading Michelle’s report took a few hours, and while I didn’t understand all the jargon, I think I got the gist of the issues and approach that her research took.

On the other hand, having read Michelle’s report has brought me no nearer to actually being able to synthesise anything more interesting than a bowl of pasta and sauce. “Reading” the string theory paper, however, has involved working through the mathematics behind each step, at great length — sometimes hours for a single line. So once I’m finished, I’ve done a substantial portion of the work that was required to write the paper in the first place. The analogy would be me reading Michelle’s paper, and then making some of the reagents too — and that would take months too.

I think this asymmetry in paper content goes a long way towards explaining another huge asymmetry between fields, namely the path of progress toward a PhD. In the case of Michelle, and most other grad students, the work they’re doing is probably what their eventual thesis is going to discuss. String theorists, on the other hand, only work on their actual thesis topic for maybe a little over a year, right at the end. I went to a string theory thesis defense last week, and the speaker had worked on three very different topics over the course of his five years — one in third year, another in fourth, and the thesis topic in fifth year.

How can this be? I’d suggest that reading even unrelated theory papers is not unlike conducting experiments in other fields. One is developing the mathematical tools and approaches that will be needed later. Once a string theorist can read any current paper in the field at least relatively quickly, then it’s a small step to starting with an idea, and then carrying out the same steps of working through the logic — only this time, one is writing a paper.

There’s no real moral to this post; I just find it interesting how superficially similar scientific disciplines can hold their real complexity in so very different areas. I may have a lot more to say about complexity shortly — just as soon as my current workload lets up enough to give me time to write some more blog posts!