Natural philosophy now – possible or necessary?

Some thoughts prompted by my reading of Unger and Smolin‘s critique and prospectus aimed at contemporary cosmology. What, I wonder, is the effect of this sort of thing? And would we like more of it, as a contribution to science criticism?

Authors tend to find critics pigeonholing their work irksome, so perhaps something interesting is happening when they make a point of claiming their work fits in a particular genre. When that genre is by common consent defunct, there is surely some important rhetorical work going on.

That’s true I think of Roberto Unger and Lee Smolin’s The Singular Universe and the Reality of Time – a book I reviewed briefly (see previous post). I had space then to note that they (mainly Unger in the sections he wrote) make much of the idea that the book wants to be a contribution to natural philosophy. But there’s more to say about what that might mean, and whether it could ever work.

Unger defines natural philosophy as neither popular science, which involves simplification, nor philosophy of science, whose “proximate subject matter” is science. The proximate subject matter of natural philosophy, on the other hand, is nature. The book, writes Unger, “intervenes, and takes a position, in the cosmological debates” with which it deals”, while “trying to describe and explore a broader range of intellectual options than is represented in the contemporary practice of the fields that it addresses”.

There are some interesting, though maybe not hugely important, contradictions here. Unger also says that natural philosophy is a “vanished genre”. On the other hand, “scientists have often used the presentation of ideas to a general educated public as a device by which to address one another with regard to the foundational matters that they cannot readily explore in their technical writings”, which suggests that it has not really vanished at all, but is disguised as a contribution to another genre – popular science that doesn’t care if it is actually popular, as it were. In practice, the main difference between their book and more reader-friendly popular science is that – while still declaring that it should be accessible to the general reader – it gets pretty technical, especially in Smolin’s portion, where I doubt that some of the physics is intelligible to people without formal training. Some of it was certainly beyond my level. That isn’t an unfamiliar sensation when I’m reading popular physics, which I’ve sampled fairly widely, but it can often be avoided by really skillful writers, doubtless at the cost of compromising some of their actual technical understanding of the physics.

Ironically, perhaps, the criticism that the physics was too hard was also levelled against an avowedly pop science book of Smolin’s, last year’s Time Reborn, which makes the same arguments as this one: time is the constant background to all events in the single universe that exists; anything, including the laws of nature, can evolve and change; there was no singularity at a point of origin; and so on. That is, nevertheless, a somewhat easier read.

In which case natural philosophy seems to mean a critique of some part of existing science, written from a stance somewhere within but also partly outside that science, which is ostensibly for everyone but aimed mainly at those very scientists. Said scientists – if I read the feedback on Smolin’s ideas right – are largely impervious to the suggestions it makes.

It all makes the possibility of reviving natural philosophy as an enterprise rather unpromising. In this case it appears to stem from a discussion that is internal to cosmology, that the authors want to take outside because it isn’t getting the response they would like inside. But the outsiders can only really say whether the position outlined appeals to their own prejudices. There is a bit of that in my little review; quite a lot more in Brian Appleyard’s longer, and more enthusiastic one. I don’t see how either of us can say whether the ideas here ought to make sense to a professional cosmologist, though. Perhaps that is a definition of professionalisation of cosmology, which happened fairly recently.

Not that the older incarnations of natural philosophy were necessarily accessible. Before the advent of a separate endeavour labelled science, the phrase occurred in the title of works including Newton’s Principia – as densely mathematical a tome as there ever was. But there was a spell when natural philosophy, by now seen as somewhat distinct from science proper, was offered in a style that was also recognisably different from purely scientific reports. An example might be Herschel’s 1831 Preliminary Discourse on the Study of Natural Philosophy, whose approach is well captured in the contents page’s summary of Part Two, which treats “Of the principles on which physical science relies for its successful prosecution, and the rules by which a systematic investigation of nature should be conducted, with illustrations of their influence as exemplified in the history of progress.” This places it, perhaps, as a work of (Whiggish) philosophical history of science, but it seems to be the kind of thing Unger has in mind when he says natural philosophy was an accepted genre up to the middle of the nineteenth century.

As I’ve indicated he is prescriptive about what natural philosophy should be like. (He is prescriptive about quite a lot of things). Its defining characteristics, he says, are that its topic is the world itself, not science. It is concerned with the direction and practice of science only as part of an argument about nature. It questions the present agenda or methods of particular sciences, and tries to distinguish what has been discovered about nature from its interpretation. The interpretation, he thinks, is where the metaphysics gets in – though I wasn’t clear after reading the book quite how the separation he counsels is to be performed. He adds that natural philosophy as he conceives it deals with problems that are both basic and general.

It’s an impressive prospectus, and the book makes strenuous efforts to deliver on these promises. In the end, though, I think the enterprise falters because an interest in natural philosophy is now optional for scientists, and few are likely to take it up. On the other hand, interested non-scientists are poorly equipped to follow the discussion of the “basic and general” problems in cosmology that the book focusses on as they simply demand too much advanced physics to follow.

So will natural philosophy remain a defunct genre, with occasional doomed attempts to resurrect it like this one? Not necessarily. Coincidentally, I re-read Hasok Chang’s Inventing Temperature, a wonderfully clear and detailed philosophical history of scientific measurement in one domain, just after getting done with Unger and Smolin. Chang is interested in the cultural bootstrapping of thermometry. Its achievement is now taken for granted. But it involved many of the finest scientists in many years of effort to slowly establish validated temperature scales, and instruments, in a world continually beset by the circularity or regress, of measurement. One can only establish a temperature by comparing its indication with some known value, but the known value has to be established in the same way.

He shows how this is not an insurmountable problem, but was eventually dealt with in a series of stages. The history goes along with a philosophical commentary which convinces that these stages were necessary, and so probably was their order. And what category shall we put this interestingly unusual book in? The author’s answer: it is a contribution to a revival of natural philosophy.

I like the book a great deal, and find it very readable. (Full disclosure: we were colleagues once upon a time.) I know that not everyone does, but I reckon any reader who was prepared to make the effort could follow all the episodes and arguments here. The tactic Chang follows, of digging into the epistemological issues posed by what seems superficially like a simple scientific accomplishment, is consistently fruitful. It certainly suggests that one way – not the only one – of writing natural philosophy now is via skilled historical excavation like this. It certainly seems to work better than taking on the most theoretically far-reaching ambitions of contemporary cosmology.

I suspect, though, that the contrast also arises because the fundamental interests of the two books’ authors are different. Chang’s basic question is how we can know anything about the material world at all. Unger and Smolin are preoccupied with the more cosmological issue of how it got to be there in the first place. Both want to practice a kind of science criticism. But there is less point in trying to find a way of doing that, I think, if it doesn’t produce results that allow the rest of us to join the conversation. That doesn’t look possible right now in cosmology criticism.

That doesn’t mean, though, that natural philosophy, in this sense I’ve just invented of science criticism for the general reader, is only a feasible thing to try for old science, tugging at historical loose ends. There are big areas of contemporary science where it can be made to work. The life sciences lend themselves to this well, for example. There are lots of very varied examples. Evelyn Fox Keller’s whole project of science criticism fits – see Making Sense of Life, for instance. Denis Noble’s The Music of Life is a more personal effort that also qualifies. It isn’t as straightforwardly accessible, but Stu Kaufmann’s Investigations might be another contribution if we wanted to fill out the category. I could go on, but that would make this post too long. Suffice to say there is enough material to give credence to the idea that natural philosophy in this vein is possible in quite a few areas of current science. It just looks like cosmology isn’t one of them.

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