Searching For The Essence Of Physical Reality : 13.7: Cosmos And Culture How much can we know of the physical world? Can we know it all or are there fundamental limits to complete knowledge?
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Searching For The Essence Of Physical Reality

We live in a quantum world. We may not know this, we certainly don’t sense it, but yes, below this experiential construct we call reality—continuous and orderly— there is a very different one, obeying a very different set of rules. To think that we are ourselves quantum creatures, made of tiny atoms vibrating frenetically at submicroscopic distances, is at least weird. The big challenging question is how to go from that world of tiny things that can’t even be called “things”—in the sense of having a well-defined spatial extension like a chair or a car—to trees, people, and stars.

Often, I use the far-away-beach image to explain the transition from quantum to everyday perception: from far away, a sandy beach looks smooth and continuous. But up close we discern its graininess, its discrete nature. The image works well until you get close to the sand. There, of course, you simply see the grains of sand; you don’t see any quantum-like behavior because the grains themselves are made of more than a trillion billion atoms.

This means that we are essentially blind to what exists at the very core of physical reality. All we have is our measurements, and they give an incomplete picture of what’s really going on.

Quantum mechanics (QM) revolves around the famous Uncertainty Principle. In practice, it imposes a fundamental limitation on how much we can know of the material particles that make up the stuff of the world. This is not to say that QM is flaky science; quite the opposite, it’s the most powerful theory we have, able to describe in great detail the results of experiments dealing with the world of the very small. In fact, most of modern technology, from DVDs and iPhones to GPSs, depends in very basic ways on our knowledge of the quantum world.

The problem with QM is not with what we know about it, but with what we don’t know about it. And since what we don’t know challenges our intuitive notions of how the world should be, there is a lot of tension among scientists on how to interpret the many quantum mysteries. At its very core, and intimately related with the Uncertainty Principle, QM establishes an inseparable relationship between what is being observed and the observer. Contrary to “normal” reality, where a table exists whether we look at it or not (yes, trees do fall in the forest when no one is looking), in the quantum world existence is determined by the act of “looking”: an object, say, an electron, is only real once someone or something (a detector) interacts with it. That is, before the measurement, we can’t say if that particular electron exists.

Since we define reality by what exists, this would imply that we, or whatever machine is doing the detecting, are ultimately responsible for determining what exists. Namely, reality is determined by interacting with it.

Kind of perplexing, especially when we contrast this with a plain table—here today and here tomorrow (if no one pushes it away or burns it). Or with your body, which tomorrow will look pretty much like it does today. Somehow, large aggregations of tiny quantum objects acquire a different kind of behavior, that we identify as our “everyday” reality of macroscopic objects.

If the essence of reality is defined by our interactions with it, then we must come to grips with two points: first, that “mind” occupies a central place in the order of things. That is, without mind there is no reality. (Not sure how an amoeba would react to this statement, but then again, it wouldn’t.) Many thinkers claim that this centrality of mind is crucial to understanding the world. Even more, that this “mind” reflects some property of the universe as a whole, us being just a part of it. Second, since we acquire information of the world through measurement, and our sense of what is real depends crucially on this information, information is the very essence of reality. Physicist Seth Lloyd, in his book Programming the Universe, argues this last point, proposing that the universe as a whole is a quantum computer. This is in the same vein of the “It from Bit” notion suggested by the great physicist John Archibald Wheeler.

Although I can see the appeal of these ideas, I can’t say I embrace them entirely. The notion that there is a universal mind, or even that our minds or that mind in general defines physical reality, seems to imbue the cosmos with a teleology that, to me, is just a modern, scientifically-inspired, metaphor for God. (Of course, you could also argue that Zen thinking does something similar; but you won’t find there the notion of cosmic purpose, i.e., of a “god.”) I prefer to see the emergence of mind—and so far the only one we know is ours—as the product of a series of random evolutionary accidents and cosmic asymmetries. To me, the wonder is that mind exists at all, given all the adversity toward life we see in the cosmos. (The universe is a pretty hostile place.)

The second point—that information is at the essence of physical reality—confuses me. I like to think that we are the ones who ascribe meaning to the material patterns we see in Nature. Every piece of matter has information in it, the “recipe” that explains how the different parts are assembled to create the whole. In a sense, through the physical sciences, we act as decoders of this information. But I don’t see how this information precedes matter. Unless you start calling the physical and chemical interactions that make up stuff “information.” But then, it all becomes semantics. Information is with matter, it can’t exist without or before it. You may get the parts that can be assembled into a watch and, without knowing how to build one, make a meaningless mess out of them. There is a huge number of ways in which these parts can be assembled, but only one will make it into a working watch. For this reason, I’d argue that “mind” (understood as the ability to purposely give form and function to matter) precedes information: we created the notion of information to help us make sense of the world.

There must be much more to reality than what we know. The question is whether we will ever grasp its elusive essence—if there is one—or if we must be content with an improving, but incomplete, picture.