Element of Surprise

I’ve finally started on The Science of Discworld, co-authored by Terry Pratchett, Ian Stewart, and Jack Cohen. It’s an offshoot from the fifth Rinceworld novel that I found tedious, except for the interesting science bits related to Ponder Stibbons and Hex, the computing machine. In The Science of Discworld, Hex is put to work to create a new universe that results in round worlds, i.e., spheres rather than discs. The wizards then try to understand aspects of this new universe. Each short fictional chapter involving the protagonists of Discworld is paired with a non-fiction chapter describing the relevant science (up to the year 1999 when the book was first published).

 

Chapter 8 (“We are Stardust”) gets us to the first bits of chemistry. The authors briefly discuss the elements of the Greek philosophers culminating in Empedocles’ theory of Earth, Air, Water, and Fire. I do the same on the first day of any introductory chemistry class I teach (for both science majors and non-majors). While I use the Aristotelian principles, I liked how the authors describe why the Four Elements theory seemed to make sense:

 

The one good idea that emerged from all this was that ‘elementary’ constituents of matter should be characterized by simple, reliable properties. Earth was dirty, air was invisible, fire burned, and water was wet.

 

They continue with a description of the work of the alchemists, who over time found these four elements too limiting. New phenomena did not fit. Hence, the alchemists introduced new elemental principles such as Sulphur and Salt. I used to talk about these in class, but I now skip them. I go straight to Lavoisier and the importance of performing separations and getting accurate measurements of weights. Lavoisier came up with 33 elements including a few errors, and we’ve been able to extend this to 118 elements today.

 

The fictional Discworld has other elements not found in our physical universe. Key among them is narrativium. As the authors write, it’s what “makes stories hang together. The human mind loves a good dose of narrativium.” I’d agree. While this certainly applies to good fiction, it equally applies to non-fiction. The best explanations tell a story that allows us to grasp what it means conceptually. But in our shaping of the narrative, we inevitably highlight some aspects while obscuring others. It’s the nature of the story-telling of science. Throughout the course of the semester, I frequently circle back to an earlier concept in chemistry and elaborate on it, making it a little more complex, and a little less simplistic from when I first discussed it with the students. I once overheard a P-Chem student tell another student, that everything they learned in G-Chem was a lie. I wouldn’t go so far; I’d say it was a simplification for good reasons.

 

The best part of stories, though, is the element of surprise! It’s what makes you sit up and pay attention! I try to regularly employ it throughout my classes. I liked that the authors of The Science of Discworld categorize their fifth element – quintessence – as Surprise! There are many surprises in science – it is indeed stranger than fiction. Fundamental physics is a great place to tell these surprising stories. We think we know what the rules are, but then… surprise! Something doesn’t quite fit and the evolving story turns toward the unexpected.

 

Chapter 12 (“Where do Rules Come From?”) is especially excellent. Having just read Fundamentals by a Nobel-prize winning physicist who goes over similar ground, I’m enjoying the juxtaposition and variety of examples generated from these two very different books. Pratchett, Stewart, and Cohen, pose the very interesting question:

 

Could the entire universe sometimes build its own rules as it proceeds?... It’s hard to see how rules for matter could meaningfully ‘exist’ when there is no matter, only radiation – as there was at an early stage of the Big Bang. Fundamentalists [i.e., strict reductionists] would maintain that the rules for matter were always implicit in the Theory of Everything, and became explicit when matter appeared. We wonder whether the same ‘phase transition’ that created matter might also have created its rules. Physics might not be like that, but biology surely is. Before organisms appeared, there couldn’t have been any rules for evolution.

 

I’ve discussed this in several blog posts, including one on biological relativity. I do think however that chemical evolution forms a continuum with biological evolution; there’s no easy clear-cut way to say where one ends and the other begins. Boundaries are fuzzy. You might be able to articulate simple rules, but it’s not so easy to determine the outcome when complexity mysteriously arises. The authors use Langton’s Ant as an example to illustrate emergence, the opposite of reductionism although possibly not its exact polar opposite. Running backwards and forwards may not yield the same results. Here’s what the authors have to say:

 

Emergent phenomena, which you can’t predict ahead of time, are just as causal as the non-emergent ones: they are logical consequences of the rules. And you have no idea what they are going to be. A computer will not help – all it will do is run the Ant very fast.

 

This last point, however, is more interesting than the authors realize. If you had a model running on an algorithm that accurately simulates the rules, and you could run the model faster than the ‘real’ system (by coarse-graining), you can now make predictions and react to them. This is the heart of anticipatory systems that make biology what it is. But where the model deviates from the real system, inconsistencies begin to appear, then build up, until at some point the model fails and the predictions become way off. How do we prevent this? By introducing another system to keep track of it – thus the different ‘levels’ in biology that act and interact with or sometimes counteract each other. Such ‘control’ systems attempt to limit the element of surprise, but cannot fully eliminate it. That’s what makes life interesting and why I think life continues to evolve. It’s built into the rules somehow, although I can’t quite articulate what those are exactly. That’s what makes a system truly complex – it cannot be subdivided into algorithms and simulated exactly. You have to live life in reality, surprises and all. Hopefully one’s life has a good dose of narrativium!