Ooh, ooh! It came, it came! I felt like a kid who'd just gotten a long-awaited toy in the mail when I opened our mailbox and saw the New Scientist cover:
What is Reality? A User's Guide to the Ultimate Question of Existence.
Finally. I'd know. What reality is all about.
I stretched out the suspense by waiting until evening to read the cover story. In the bathtub, immersed in relaxingly hot water, a glass of red wine and highlighter in hand (not at the same time).
I wasn't disappointed. Right away I liked the concise focus of the "Defining Reality" section. What do we mean by reality? Jan Westerhoff makes some reasonable suggestions, after discussing less plausible options.
There are two definitions of reality that are much more successful. The first equates reality with a world without us, a world untouched by human desires and intentions. By this definition, a lot of things we usually regard as real - languages, wars, the financial crisis - are nothing of the sort. Still, it is the most solid one so far because it removes human subjectivity from the picture.
The second equates reality with the most fundamental things that everything else depends on. In the material world, molecules depend on their constituent atoms, atoms on electrons and a nucleus, which in turn depends on protons and neutrons, and so on. In this hierarchy, every level depends on the one below it, so we might define reality as made up of whatever entities stand at the bottom of the chain of dependence, and thus depend on nothing else.
This definition is even more restrictive than "the world without us" since things like Mount Everest would not count as part of reality; reality is confined to the unknown foundation on which the entire world depends. Even so, when we investigate whether something is real or not, these final two definitions are what we should have in mind.
Delving deeper into the implications of these definitions, the New Scientist cover story asks such questions as:
Is matter real?
Is everything made of numbers?
How do we know reality isn't an illusion?
Are we in a simulation, not "base" reality?
Quantum theory seems to show that probability waves don't turn into real objects until an observation occurs. This introduces consciousness into the what is reality? equation. However, Westerhoff points out that some aspects of particles are dependent on measurement, and some aren't.
Yet if we accept that the wave function must collapse as soon as consciousness enters the measurement, the consequences are even more curious. If we decide to break off the chain at this point, it follows that, according to one of our definitions of reality, matter cannot be regarded as real. If consciousness is required to turn ghostly probability waves into things that are more or less like the objects we meet in everyday life, how can we say that matter is what would be there anyway, whether or not human minds were around?
But perhaps this is a bit too hasty. Even if we agree with the idea that consciousness is required to break the chain, all that follows is that the dynamic attributes of matter such as position, momentum and spin orientation are mind-dependent. It does not follow that its static attributes, including mass and charge, are dependent on in this. The static attributes are there whether we look or not.
Nevertheless, we have to ask ourselves whether redefining matter as "a set of static attributes" preserves enough of its content to allow us to regard matter as real. In a world without minds, there would still be attributes such as mass and charge, but things would not be at any particular location or travel in any particular direction. Such a world has virtually nothing in common with the world as it appears to us.
...It seems that the best we are going to get at this point is the claim that some things are there independent of whether we, as human observers, are there, even though they might have very little to do with our ordinary understanding of matter.
So what about the other strong definition of reality, the foundation for everything else? Consciousness apparently isn't that foundation, since some things (such as the mass and charge of particles) would exist whether or not a conscious observer is aware of them.
This was the most interesting part of the article for me.
When I was researching my first book about mysticism and the new physics (I'm slowly working on finishing up a rewrite and getting it back in print), I read a lot about how various scientists and philosophers interpret quantum theory.
There's no agreement about what quantum theory tells us about the foundation of reality, even though it is able to make marvelously precise predictions of goings-on in the atomic and subatomic world. Thus the meaning of quantum theory is open to question, while the mechanics are pretty well settled.
Offering an example of the traditional Copenhagen interpretation of quantum theory, says Westerhoff, particles pop into a definite existence "when the system to be measured (the electron) interacts with the measuring device (the phosphor screen. For this reason, it has to be assumed that the phosphor screen will not itself exhibit the particular quantum behaviour shown by the electron."
This is where weirdness starts to creep in. Well, actually weirdness is all-encompassing in quantum theory, because it so far removed from how the everyday world appears to us. So let's say increasing weirdness starts to creep in.
Measuring devices, whether a machine or the human mind, are medium-sized material things. These things are made out of the tiny subatomic particles which, says the traditional interpretation, come into being when measured by a medium-sized material thing.
Weird! This is how Westerhoff's article ends.
And this is where the circularity comes in. We analyse the everyday world of medium-sized material things in terms of smaller and smaller constituents until we deal with parts that are so small that quantum effects become relevant for describing them. But when it comes to spelling out what is really going on when a wave function collapses into an electron hitting a phosphor screen, we don't ground our explanation in some yet more minute micro-level structures; we ground it in terms of readings made by non-quantum material things.
What this means is that instead of going further down, we instead jump right back up to the level of concrete phenomena of sensory perception, namely measuring devices such as phosphor screens and cameras. Once more, we are in a situation where we cannot say that the world of quantum objects is fundamental. Nor can we say that the world of measuring devices is fundamental since these devices are themselves nothing but large conglomerations of quantum objects.
We therefore have a circle of things depending on each other, even though, unlike in the previous case, mental objects are no longer part of this circle. As a result, neither the phosphor screen nor the minute electron can be regarded as real in any fundamental sense, since neither constitutes a class of objects that everything depends on. What we thought we should take to be the most fundamental turns out to involve essentially what we regarded as the least fundamental.
In our search for foundations, we have gone round in a circle, from the mind, via various components of matter, back to the mind - or, in the case of the Copenhagen interpretation, from the macroscopic to the microscopic, and then back to the macroscopic. But this just means that nothing is fundamental, in the same way there is no first or last stop on London Underground's Circle Line. The moral to draw from the reductionist scenario seems to be that either what is fundamental is not material, or that nothing at all is fundamental.
So there you are, believers in something supernatural: some scientific hope. Either what is fundamental is not material...
Yes, that's a possibility. But it requires a belief in an unobserved reality for which there's no demonstrable evidence. This world, on the other hand, is clearly evident -- albeit mysterious.
Which leads to the other possibility: Nothing at all is fundamental.
Buddhists are smiling at that statement. Emptily.