The limits of knowledge: Things we'll never understand (?)

Michael Brooks has an article over at New Scientist on the limits of knowledge, exploring the world of fundamental questions on the nature of reality that we may never be able to understand (Linkage: The limits of knowledge: Things we'll never understand - space - 09 May 2011 - New Scientist). We live in an age that takes scientific advancement for granted, where computer speeds double every eighteen months and where Hubble publishes breathtaking pictures of rotating galaxies billions of light years away and billions of years in the past. Indeed, we're so immune to the pace of scientific progress that such wonders don't even make the front page any more - they're relegated to the background noise behind the petty political squabbles we fight and Justin Beiber's haircut (appalling, I know). I think the sentiment among the general public is that the discoveries and advancements we make are regularly scheduled; perhaps to the point that no one would even really begin to notice them until they stopped. Is that possible? Will we reach a time where we run up against a gigantic mental roadblock firmly in the way of progress for the first time in humanity's scant existence?

The question isn't as dire as it sounds, and being an optimist, I don't think such limitations should really be taken seriously, but let's explore them for a moment and see what they may have to offer. Brooks's piece begins with a rather thought-provoking and frightening (because I don't think of myself as a chimp) quote from the UK's Astronomer Royal Martin Rees that puts the concern into high relief:

A chimpanzee can't understand quantum mechanics. It's not that a chimpanzee is struggling to understand quantum mechanics. It's not even aware of it. There is no reason to believe that our brains are matched to understanding every level of reality.

At first glance this sounds completely reasonable, and it is. There is no real way of being one hundred percent certain that we are even missing some fundamental aspect of our reality from our scientific framework. In fact, we may never really have the problem of running up against a "knowledge wall" at all. We may one day believe that we've found a complete Theory of Everything, verified time and again by experiment and still be missing some piece of the puzzle that we're not even aware exists. If we were to magically create the technology necessary to completely and thoroughly explore our universe and map it in complete detail, we'd never be able to be one hundred percent certain that there is or is not something beyond what we see, curled up in another dimension or nestled in a floating brane a hair's breadth from the one in which our universe is currently residing. In that respect, science could truly be endless, like a stack of matryoshka dolls continuing ad infinitum. Of course this lends itself to tons of absurdities. By the same logic I can argue that an army of invisible and subatomically small Wookies are responsible for gravity because you can't disprove it. So where do we draw the line? What makes something reasonable and something else not? Theoretical physics is pushing the envelope of the believable every single day, offering up explanations for the behavior of everyday objects that thoroughly stretch, if not completely defy, the imagination. (Just flip through the Wikipedia page for M-Theory to get a taste of multidimensional superstring theory to see what I'm talking about).

Indeed it does.

So what do we do about this dilemma? What science should we trust and what science do we hold suspect? How do we ever know if we have reached a true, complete theory of reality or if we need to keep looking? The first step is recognizing the limits you're working with. Einstein recognized this very early on and I don't think I can really improve upon his metaphor:

Physical concepts are free creations of the human mind, and are not, however it may seem, uniquely determined by the external world. In our endeavor to understand reality, we are somewhat like a man trying to understand the mechanism of a closed watch. He sees the face and the moving hands, even hears its ticking , but he has no way of opening the case. If he is ingenious he may form some picture of a mechanism which could be responsible for all the things he observes, but he may never be quite sure his picture is the only one which could explain his observations. He will never be able to compare his picture with the real mechanism and he cannot even imagine the possibility of the meaning of such a comparison. 

Sounds pretty much the same as Rees - but the clock analogy here is much more powerful. Any number of explanations for how the watch works can be "correct" if they make testable predictions about the watch's behavior and if they mesh well with other things we observe to be true about our universe. But which is really, really correct? The honest answer: it doesn't matter. They all are. Scientific theories are simply models and approximations, nothing more. We are simultaneously a part of reality and divorced from it in a mentally abstract way. These models are correct so long as they are useful to us in explaining the world around us in a coherent way. My Wookie gravity theory could be correct, but, sadly, offers no basis for experimental confirmation or utility in explaining anything else around me. In that respect, even if at the fundamental level it were true, it's useless and therefore not worthy of my further pursuit. Don't get me wrong, it's really fun to daydream, and not everything in life has to serve some purpose or be branded useless, but this method of thinking does offer us a system through which we can advance and sort through the overwhelming number and variety of scientific theories out there today.

Brooks divides his problems into three categories, providing examples of each to highlight the limiting problems we face in fields from biology to physics and astronomy. Brooks:

There are some things we can never know for sure because of the fundamental constraints of the physical world. Then there are the problems that we will probably never solve because of the way our brains work. And there may be equivalents to Ree's observation about chimps and quantum mechanics - concepts that will forever lie beyond our ken.

Brooks himself is quick to point out that we often times can make tremendous progress once we know something about what we "can't" know, like with Heisenberg's Uncertainty Principle. The optimist in me would like to argue against all three of his points. Firstly, the history of scientific progress has been a creative one. By the end of the nineteenth century, many in the science profession advised young undergraduates against going into the field of physics because everything worth knowing had already been found. Luckily for us, Einstein ignored such presumption and provided a paradigm shift that has endured for well on a hundred years. What it will take for more progress once a similar 21st century wall is reached may be similar creative thinking. Fundamentally different ways of thinking that cast reality in a new light, which promising new ideas like the Holographic Principle may potentially do. Perhaps we've learned all we can on this "level." What we should be seeking is a deeper one from which the things we observe that give us problems emerge so we can place them in context. As for how our brains work, humans have proven ingenious at solving problems in the short time we've been around. Where our own brains have fallen short we've supplemented them with printed libraries, the salons of the Enlightenment, computers and calculators and the group thinking of the internet. As a (more or less) cooperative species, I don't take such biological limitations seriously. For the last, we return to Einstein's watch. Embracing a little subjective reality, if a concept is "forever beyond our ken," it hardly seems worth worrying about as it becomes something that transcends our experience of reality. I don't want to get into metaphysics here, but from a scientific perspective, if these concepts can't be understood using the logic we're capable of, then we'll remain as blissfully unaware of them as we are of the army of Wookies holding your feet to the ground and keeping the sun a nice, neat, contained (and useful) nuclear explosion for us.