The unreality of physics

Last one on my catch-up list before I begin blogging books.

This is a very nice video which gets the closest I've ever seen to presenting a comprehensible version of the notion of wave-particle duality. I should warn you that I don't think it quite gets there. But it does open a promising avenue of inquiry.

To do this requires accepting that we are prisoners of perception, that what we can sense is not necessarily the whole of reality. This should not pose anyone any great difficulties : we know the Universe looks radically different at different wavelengths, we have no problem with the notion of animal senses being different to our own.

But we might have to go further than this. We might have to accept not only is our perception limited, but it is also just wrong - that reality is nothing like our perception of it. To me this is intuitively daft : we can only define things by how we perceive them, so anything else is a waste of time. Sure, there might be some pseudo-platonic form of an apple, but since we can never have any knowledge of what that is, it's pointless to speculate.

On the other hand, I'm comfortable with the idea of multiple dimensions. Objects existing in a fourth spatial dimension would appear magical to us, able to appear and disappear, pass through walls, and continuously change shape as they moved through a dimension our brain appears fundamentally unable to grasp. So in that sense I can accept a non-perceptible aspect to reality.

A better explanation, however, came in a recent discussion*. Simply put : there are no things, only stuff. A line they wisely rejected from The Matrix in favour of "there is no spoon"...

* Also featuring Xeno's Boner, for some reason.

What this means is that all language is a descriptive mental construct. To go back to Plato, "Names would have an absurd effect on the things they name, if they resembled them in every respect, since all of them would be duplicated, and no-one would be able to say which was the thing and which was the name." A name is not the thing, the map is not the territory. Or recall the excessively useful video about chairs (see also this). 

That is, there is something real out there that induces perception in here : we label its components (the "things"), but the real "stuff" does not have any associated chairness or planetyness about it at all. The "things" are just labels, the "stuff" is very real. This, I think, is entirely compatible with saying an apple is what induces the perception of an apple. It simply surrenders the notion of an apple of having any fundamental, atom-like reality : all it "really" is is a collection of particles.

Now this is only an analogy, but a useful one. If we accept for a moment that atoms are the most fundamental component of reality, then everything we see is just atoms. Clouds are how we label collections of water molecules in gaseous phase. Forks are collections of iron and carbon atoms arranged in a particular configuration. Bishops are collections of numerous atoms in complex configurations : neither bishops nor forks nor clouds are anything except our labels for different atomic structures; they do not exist in any strict physical sense except by linguistic convention - we can reduce everything, in this view to atoms.

The trick is to remember that this is an analogy. Atoms, of course, are certainly not the most fundamental component of reality - we have no idea at all what this might be. But it turns out we might not need to. On at last to the video.

This begins with a statement that perhaps instead of modelling the Universe, all science can do is model our observations of it. We model our knowledge, not the stuff itself. From the above, hopefully this should not be too great a leap. It's a subtle difference from the usual assumption that our models steadily improve and tell us more and more about the Universe - but the distinction that all they do is tell us more about our observations is ultimately not the same statement at all.

Rather than trying to model actual physical reality, this interpretation allows for a quantum theory which deals purely with information. And the building blocks of all our observations, if not necessarily reality itself, is certainly information. And this we can indeed reduce to a fundamental level : the bit. It appears that an information-based theory of quantum mechanics is able to reproduce quantum weirdness like entanglement and wave-particle duality.

According to this theory, since the basic unit of information is binary, you can ask a series of yes/no questions to get information about the behaviour of a quantum system. Ultimately the system only has a finite amount of information to work with, so if your experimental setup demands more, you get wave-like randomness...

But alas, dear reader, this is where the video's genius comes to an end. Frankly this feels a bit like getting the golf ball onto the green and then running away, or reaching the point of climax but then deciding to take a cold shower... if it could only follow through this chain of thought a little more ! Walk me through the double-slit experiment, for pity's sake ! Tell me how the limited information manifests itself in that experimental setup, and I'll be your friend for life !

Ah well, can't have everything. Provocative, even so.