Posts tagged ‘renormalisation’

An intriguing but puzzling paper from Simon DeDeo.

He begins by noting that while physics is good at generalised predictions, it fails to predict the particular. Working at the blackboard we can deduce laws governing the genesis of stars, but nothing about the specific existence of the blackboard. He sees this as a gap and for reasons that remain obscure to me he sees it as a matter of origins; the origin of society, consciousness, etc. To me, it’s about their nature; assuming it’s about origins constrains the possible answers unnecessarily to causal accounts.

Contrary to our expectations, says DeDeo, it’s relatively easy to describe everything, but hard to describe just one thing – the Frame Problem is an example where it’s the specifics that trip us up. By contrast, with the Library of Babel, Borges effortlessly gave us a description of everything. The Library of Babel is an imagined collection which contains every possible ordering of the letters of the alphabet; the extraordinary thing about it is that although it is finite, it contains every possible text – all the ones that were never written as well as all the ones that were.

We could quite easily write a computer program to find, within the library, all occurrences of the text string ‘Shakespeare’, says DeDeo; but there’s no way of finding all the texts about Shakespeare that make sense. That’s surely true. DeDeo says this is because what we’re asking for is more than just pattern matching. In particular, he says, we need self-reference. I can’t make out why he thinks that, and I’m pretty sure he’s wrong, though I might well be missing the point. To me, it seems clear that in order to identify texts that make sense, we need to consider meanings, which are not about self-reference but reference to other things. In fact, context and meaning are of the essence. One book from the Library of Babel contains all books if we are allowed to apply to it an arbitrary interpretation or encoding of our choice; equally any book is nonsense if we don’t know how to read it.

But for DeDeo this is a truth with a promising mathematical feel. We just need to elucidate the origin of self-reference, which he thinks lies in memory at least partly. The curious thing, in his eyes, is that physics only seems to require (or allow) certain levels of self-reference. We have velocity, we have acceleration, we have changes in acceleration; but models of worlds that have laws about third- or higher-order entities like changes in acceleration tend to be unstable, with runaway geometrical increases messing everything up.

So maybe we shouldn’t go there? The funny thing is, we seem to be able to sense a third-order physical entity. A change in acceleration is known as ‘jerk’ and we certainly feel jerked in some situations. I have to say I doubt this. DeDeo mentions the sudden motions of a lift, but those, like all instances of jerk, surely correspond with an acceleration? I wonder whether the concept of jerk as a distinct entity in physics isn’t redundant. For DeDeo, we perceive it through the use of memory, and this is the key to how we perceive other particularities not evident from the laws of physics. We tend to deal with coarse-grained laws, but the fine-grained detail is waiting to trip us up.

It’s not all bad news; perhaps, DeDeo speculates, there are new levels we have yet to explore…

I’m very unsure I’ve correctly understood what he’s proposing, and the fact that it seems to miss  the real point (meaning and context) might well be a sign it’s me that’s not really getting it. Any thoughts?