Can We Trust Our Brains?
I have recently been repeatedly confronted with the philosophical quandary of whether or not our perceptions of reality can be trusted, or if our internal models of the world around us are bound to be riddled with flaws and misrepresentations. A fellow blogger has spurred be to put down my thoughts in writing.
I think you have to begin by admitting that we can never know if our senses do justice to reality, because we have no other way to gauge their efficacy than by our senses themselves. However, ultimately, I think they do a pretty damn good job.
I’ve found evidence for this in the fact that a brain is, in its most basic form, an input-output system. Input stimulus: output response to stimulus. Evolution tunes the system to give the proper response to the proper stimulus, and therefore to be faithful to reality. For example, we have a vermicompost box, and when we want to get the worms to move in a certain direction, we expose them to light. They promptly wriggle in the direction of the nearest shade. If their flee response weren’t faithful to reality, they’d fry to death, or waste valuable energy wriggling when there was no sun.
Granted, the human brain is more sophisticated than that, because it has a complex intermediate step of model building based on memory. This apparatus allows synchronic tuning of responses to stimuli, as opposed to letting natural selection tune them. However it’s still just an elaborate version of “when the world is this way, respond in that way.”
Therefore, if you’re not building an accurate model of the world around you, then your brain isn’t performing its function. Evolution should then select for brains that make increasingly accurate models of the surrounding environment, or at least as accurate as any given organism needs (a human needs no sense for surface tension, but a water strider needs no sense for vertical orientation). Sure, there are glitches in the system, and they give rise to models that belie reality, but only in trivial ways: like optical illusions, pareidolia, and religion.
And there’s my daily epiphany: religion belies reality only in trivial ways. The belief that there is an invisible man in the sky who sees everything you do fits neatly into the gaps in our perception in such a way that it cannot be disproven, and it does not (often) dictate our reactions to stimuli. If it interfered with our model-building apparatus in either of these ways, evolution would have–and modern science could have–disposed of it quickly.
In closing, I’d like to analogize the brain to a house; the function of the brain is to construct models of the world, and the function of a house is to protect its inhabitants. You can build a house out of all kinds of things (aluminum, bricks, adobe etc.), and while you’ll have different engineering strategies based on the materials you are using–and different drawbacks with each–the end goal is still to create shelter (in the case of the brain, to build faithful models). Evolution set us on a particular path, with a particular set of materials–namely, the more basic reptilian and mammalian brains–and the drawbacks inherent thereto. The evolutionary history of the brain presents a unique set of obstacles to building a functional model-building apparatus, and has crucially informed its eventual architecture, in the same way selecting Play-Doh as the building material for your house would present a unique set of obstacles to its construction. Surely, it’d be better to choose bricks than Play-Doh, but evolution won’t let you switch materials mid-build, but we got as close as we could. Obviously, the materials we got stuck with weren’t that bad, because we’re still here. And our model building apparatus can’t be that bad either.
Tags: Brains, Evolution, God, Model Building, Pareidolia, Reality
June 3rd, 2009 at 2:37 pm
Follow up:
This is not to say that the existence of god is a trivial question, or one that has no humanly ascertainable answer. Rather, the belief in god is no more a direct affront to objective reality than is the inability to perceive both directions of spin in this dancer. They are both illusions common to human perception; faults in the building materials of our brain/house. But they are usually trivial in terms of our ability to construct a coherent world model.
However, the existence of god has some non-trivial philosophical and social ramifications, so regardless of the pervasiveness or immanence of the illusion, it’s still far more significant than a simple optical trick, and it’s still one we should go to great lengths to dispel. Especially considering this illusion has a curious habit of polluting otherwise functional models.
June 3rd, 2009 at 8:25 pm
A very complex issue which deserves a book length reply which I am too lazy to write (and which I’m sure has been the subject of many books). I will only note a few things:
As I’m sure you are aware, many if not most people have some brain dysfunction (colorblindness comes to mind, the tendency to addiction is another) and the brain is certainly an imperfect instrument for processing reality. Those imperfections are passed along from generation to generation and still the race survives due to sheer numbers and the willingness of humans to support those whose flaws would otherwise cause their demise. (We will rescue a nonswimmer who foolishly jumps into the deep end of the pool and would otherwise drown.) Once a species reaches a critical mass, it is inevitable that some will survive until a cataclysmic event happens to wipe it out. (Frogs are currently dying off because of a virus they can’t resist.) This too will happen to humans at some point unless they survive long enough to escape their small environment by developing the technology to seed themselves beyond Earth. (We’ll probably blow ourselves up long before that happens.)
As far as the existence of “God” is concerned, I agree that for the most part, it is a trick of the brain. Man has created God in his own image, with his flawed brain. The brain tricks you into thinking you are the center of the universe and can imagine “God” or “no-God.” If there is “no-God,” then you are the highest form of life imaginable. (Oh, joy!) Hubble has shown us that the universe is so much larger than anyone could imagine when Gods were being imagined that our brains are not sufficient to process what might be.
June 10th, 2009 at 8:22 pm
Damn, all that brain power I put into that reply and not even one comment following to rebut or agree, even from the blog master. That leaves only two conclusions: the subject was so lame and my reply was so stupid that it deserves being ignored, or my reply was the final word on the subject (hey, I’m not that smart). Our brains and our relationship to God or no-God are important. Could we have a little dialogue here?
June 17th, 2009 at 11:45 am
I think you pretty much encapsulated the dilemma of God/No-God, although I’d put a different spin on it.
The fact that we’re preoccupied with the dilemma in the first place is a function of our imperfect brains. Detection of causality is an important ability for a brain used in complex social architectures, and ours are over-primed to detect it. So, when there is no apparent ’causer’ we make one up.
I think we should be willing to accept the fact that, although our brains have difficulty maintaining a model in which there is no ultimate cause, and in which we are but a trivial sidenote to the history of the universe, there is no mystical magical hoo haa beyond that which we can detect with our senses, and extended senses, by which I mean mathematics and science.
Anything else is an illusion. Sorry to be such an existentialist.
One final point, I’d like to make about your post: if we’re being honest with ourselves at all, I don’t think there are any circumstances under which humans could call themselves the “highest form of life.” Particularly because that implies some kind of ladder of sophistication, which most people, myself included, reject.