Apologies for the pun, but a bit of prose for you. The power was out, so I just collected some recent thoughts. They don’t rhyme, but I hope they reason.

How Do You Know?  (bulk of essay after the jump)

It is trivially simple to demonstrate the limitations of our perceptual systems, of our memories, of our rationality. Our senses are subject to illusions—we see things that are not there, and miss things that are. Some of the time this is the result of learning, but some are built into the sense organs themselves (such as the illusory dots seen in a Hermann Grid), and cannot be unlearned. Our memories are subject to systematic biases and distortions. It is not at all uncommon to have vivid memories of events that did not happen, and it is even more common to have no memory of events that did. Our supposedly rational thinking falls prey to heuristic biases, resulting in “predictably irrational” decision-making.

And this is the case when we are dealing with real-world phenomena. Even when there is a real object to perceive, we are imperfect perceivers, imperfect rememberers, imperfect thinkers. Over a century of research on these subjects leads inescabably to this conclusion.

Fortunately, we are able to refine our observations, and to check them against the observations of others. We converge on common understanding (the dots in the Hermann Grid are not real) and sometimes explanation (they are an artifact of perceptual fields and lateral inhibition in the neurons of the retina); we standardize our observations, operationalize our measurements, and collectively make sense of the world despite the occasional nonsense of our senses.

The scientific community engages in this refining of observations as an entity; the scientific method imposes an order on this community such that it is, in the long run, self-correcting. There is no shortage of ideas that did not pan out (N Rays?), nor is there any shortage of ideas that were outrageous at first blush, but which proved their merit through empirical demonstration (from heliocentrism to quantum physics).

We know our observations may be faulty when we look at the real world. We are creatures of the real world; our bodies, our perceptual systems, are real, and are limited. But what about our perceptions of non-real entities? There is no evidence of a second perceptual system for these, so we must use our, flawed, imperfect system, with its inherent limitation. What are the implications of this observation?

Let us assume that the Abrahamic God exists. Could we know it?

C. S. Lewis proposed the “Liar, Lunatic, or Lord” trilemma. We do know that liars and lunatics exist; how would we go about determining whether a prophet was speaking the truth? In matters of the real world, we have a (wait for it….) real world to examine, to compare our notes with others, to manipulate and measure. A god that exists outside of this real world would not be available for examination.

Suppose you yourself were that prophet, and god spoke to you directly; how could you know this? We can be utterly certain of the truth of a false notion. We can swear in court, honestly believing, something that is not so. The certainty with which we believe a thing is no guarantee of that thing’s truth.

If this were science, we would be forced to look for consensus, for agreement with others looking at the evidence. Do the religions of the world describe god in the same way? Clearly, even the Abrahamic religions disagree with their cousins enough to war with them. Different Christian sects may kill and die over disagreements.

In the theism-atheism debates, we are often reminded that it is not the place of science to say there is no god. God, as an unfalsifiable hypothesis, is beyond the reach of science. But science does have a lot to say about how we believe, and how we perceive; we absolutely can say that some of the claims of religious believers are beyond the reach of human perception and understanding. They cannot know what they claim to.

The Abrahamic god is claimed to be omniscient and omnipotent, for example. Let’s assume that this actually is the case. Could we know it? Can we discriminate between extraordinary superhuman (but not omnipotent) power and omnipotence? We could look to psychophysics, and note that perception is reliable only over particular ranges of stimuli. We could look to pain perception, and note that “on a scale of 1 to 10, where 10 is the worst pain imaginable”, the high end is dependent on the experience of the individual. Stubbing your toe may be the worst pain imaginable… until you get that first migraine, or kidney stone, or labor pains.

Can we know omniscience? A three-year-old once thought I was omniscient. I can only know if god knows the right answers to questions that I can know the right answers to! The less I know, the easier it is to fool me that you are omniscient. As Nelson Muntz put it, “It’s like asking the square root of a million; we may never know.”

I will grant, none of this makes a god impossible. Well, for some definitions of “a god”. A non-interventionist god can never be disproved. But of course, a non-interventionist god would never have given any human a reason to believe in it in the first place. A non-interventionist god would be indistinguishable from a fictional god. An interventionist god, one that makes itself known, one that tweaks the real world, may or may not (depending on characteristics) be possible, but could conceivably be testable and falsifiable. If a god answers prayers, heals the sick, moves mountains, and does so with the sort of reliability claimed by followers, these are empirically testable claims. Which, as a rule, god fails.

*****(separate musing)******

I have heard some say that the evidence for god is all around us—that god is everywhere, that without god there would be nothing. Strangely enough, psychophysics can teach us a bit about this as well.

Our sensory/perceptual systems have evolved (or, we could assume, were designed) to detect contrasts and changes. Change is informative. Differences are meaningful. The separation of figure from ground has evolutionary consequences. The presence versus absence of something is meaningful; constants tend to disappear. Stabilized retinal images literally disappear (convenient, or you’d be looking at the world through the spiderweb of retinal blood vessels); constant sounds fade, and the aroma of a dorm room ceases to offend, with sufficient exposure. If god is all around us, we have no “no god” condition to compare to. We cannot know that the condition we are observing is the “god” or “no god” universe, because the constant presence is indistinguishable from the constant absence. Yes, it is entirely possible, logically (that is, we cannot falsify it), that we are in the “god” universe. But even assuming that we are, we could not know it; it would be perceptually identical to the no-god universe.

“How do you know” is an important question, and it is one that science can, should, and does answer. The scientists who study belief don’t get the cool tv shows with astrophysics or dinosaurs, but their contributions can be every bit as valuable.