“Beauty is truth, truth beauty, – that is all ye know on earth, and all ye need to know” -Keats
Lets begin with basic epistemology; the basis for all sensation and awareness is the physical reality we find ourselves in. Reality does not care what we think about it, or what we believe. As Philip K. Dick once said “Reality is that which, when you stop believing in it, doesn’t go away.”
This is sometimes referred to as the primacy of reality. When analyzing/viewing/interacting with reality, we have numerous methods and devices available to us that we may use to gather and analyze data, including but not limited to our five senses and scientific instruments. From those data, we abstract initial 2nd order models, those of perception. (Seeing is not the same as perceiving – perception is cognitive. If photons bounce off a camouflaged moth and hit your eye, you have seen it. But unless you realize it is a moth, you have not perceived it.)
And, as modern Physics proves beyond any supportable doubt, those 2nd order models are quite often wrong. Examples range from the trivial (refraction of light in a glass of water making a spoon look bent) to the profound (a photon can be a particle and a wave at the same instant, can be in two places at once and can actually produce an interference pattern with itself.) From our 2nd order perception, we abstract 3rd order models. Most often these models are a linguistic gloss, but sometimes they are a mathematical model. Ultimately this is a distinction without a difference, as mathematics is a language much like any other.
It is vital to note, however, that these abstractions lack the primacy of reality. “The map is not the territory, the menu is not the meal.”-Korzybski
Being able to honestly say “I don’t know” is not weakness. It is the beginning and the foundation of wisdom, intellectual strength, and power.
Due to the nature of abstraction, there is always a degree of imprecision in our statements about the world around us; we craft models which aim to best approximate reality. These models are, properly understood, analogies which lack the primacy of 1st order phenomena. Additionally, there are physical constraints that prohibit absolute certainty and render reality probabilistic.
Because of this fact, and in part because of the nature of reason itself, proper epistemology is based on a default negative premise that has to be falsified in order to provisionally hold any positive position or claim. That default position is known as the null hypothesis (NH). The NH is essentially a denial of whatever is being claimed.
If you say a drug cures cancer, the NH is that it’s no more effective than a placebo. If you say that the moon is made of green cheese, the NH is that it is not. If you say that an untestable, unobservable, unfalsifiable, undefined, magical entity exists, the NH is that it exists and anybody disagreeing with you is either insane; an agent of that alleged entity’s equally untestable, unobservable, unfalsifiable, undefined, magical archenemy; or that they’re only pretending not to share your belief since they secretly believe in and hate the alleged entity. Of course. Of course.
Those claiming the existence/nature of something must falsify the null hypothesis with evidence. Absent a falsified null hypothesis, the NH must stand as the most reasonable answer, unless and until additional evidence is presented. To put a finer point on it, absent evidence sufficient to falsify the NH, the NH remains our default answer. However, this, in and of itself, does not mean that an unfalsified NH proves that the claim being made is false. What it proves is that the claim being made cannot be supported and as a result there is no reason to accept it as true.
“Those who can make you believe absurdities, can make you commit atrocities”-Voltaire
Lacking a falsified NH, there is no reason to believe in any claim. Provisional non-belief, or even provisional disbelief, are both fully justified. One may also go further than disbelief, into active refutation of claims. If I tell you that I have a full sized elephant under my bed and you do not find one, the NH stands unfalsified. If you then apply reason to the situation, you will recognize that, in this case, absence of evidence is indeed evidence of absence.
It should come as no surprise, then, that faith proves nothing about the external world. Faith does not, and can not, falsify the NH, because it is not evidence of anything external to the state of someone’s mind. Wish into one hand, spit into the other. See which one fills up first. Or, as Nietzsche put it: “A casual stroll through the lunatic asylum shows that faith does not prove anything.”
While virtually all fundies understand this as long as their ox is not being gored, they seem to very conveniently forget this principle in situations where remembering it would challenge their faith. Few fundies will tell you that because we cannot confirm nor deny that there are vampires which walk among us, assuming human form, with magical powers that make them totally undetectable by any and all scientific means… that we should all walk around draped in garlic. But they will tell you that because we cannot confirm or deny their deity, their deity is real, and we should all walk around draped in faith. This double-standard-based-irrationality is the basis for Pascal’s Wager.
Some folks are ‘lucky’ enough to be immune to cognitive dissonance, I suppose.
To return to an earlier point, when the NH is not falsified, there are three general options. The first is to have a negative lack of belief. That is, one might say “Well, I’m not convinced. I do not hold your belief.” The second is to have a positive disbelief. That is “I am not only not convinced, but I believe that you are wrong.” The third is to consider the claim to be unworthy of recognition, let alone further contemplation. Some claims are gibberish, nonsense, word salad. They are Not Even Wrong (http://rationalwiki.org/wiki/Not_even_wrong).
One cannot, for example, extract semantic meaning from, let alone evidence to support or refute, a statement like Chomsky’s “Colorless green dreams sleep furiously.”
All of this goes a long way to explain why fundies so often commit the fallacy of Shifting the Burden of Proof while they demand that others refute their unproven assertions; unable to prove their own claims, they attempt to make others disprove a claim about an alleged entity which, by their own definition, is untestable, irrefutable, and beyond reality itself. Naturally, all a rational fellow must do when faced with such an opponent is to point out that they haven’t carried their claim, and that he has no obligation to refute something which has no support in the first place.
Or, to use Hitchen’s Razor: “That which can be asserted without evidence, can be dismissed without evidence.”