Posted: Dec 18, 2011 10:44 am
by jlowder
Calilasseia wrote:Except that Draper misses the point.


Hi Calilasseia -- No, with all due respect, YOU have missed the point. You are simply confused about the difference between prior probability, explanatory power, and final probability.

Prior probability: this is a measure of the plausibility of a hypothesis, i.e., its probability independent of the evidence to be explained.
Explanatory power: this is a measure of how well the hypothesis yields the data, i.e., the probability of the evidence conditional upon the hypothesis and the background information.
Final probability: the probability of the hypothesis after assessing the prior probability and explanatory power, i.e., the probability of the hypothesis on the background information and the evidence to be explained.

If someone makes shit up, we can evaluate their claims in terms of the distinction between prior probability and explanatory power, and show that whatever evidence they offer for their claims doesn't yield a high final probability.

Calilasseia wrote:Which consists of demonstrating that anyone can make shit up and pretend that reality conforms thereto, and that there is no essential difference between shit made up recently to provide a demonstration of this, and shit made up 3,000 years ago by people who thought that their magic man actually existed. At least, no one has been able to provide substantive demonstrations that their pet mythologies are anything other than assertion-laden made up shit. Trying to claim, for example, that 3,000 year old mythological made up shit is somehow "more valid" than recent made up shit, because the recent made up shit was deliberately constructed to expose the made-up-shitness of supernaturalism full stop, whilst the 3,000 year old made up shit was concocted by people who actually believed it, misses the target by light years.

That paragraph is not of obvious relevance to anything I or Draper have written. First, "validity" is a concept which applies only to deductive arguments, not inductive arguments. The issue is not validity but inductive correctness. Second, you seem to be under the mistaken impression that just because theism has a higher prior probability than other forms of supernaturalism, that it somehow follows that theism has a high final probability. Final probability is the product of prior probability and explanatory power. Let's make up numbers solely for the sake of illustration. Suppose that the prior probability of deism is .1, the prior probability of theism is .15, and the final probability of theism with respect to the evidence is .0001. Would that bother you? If yes, why?

Calilasseia wrote:Likewise, trying to erect some bizarre taxonomy of made up shit, on the basis of some probabilistic calculus, is a wasted exercise. At bottom, made up shit is precisely that, and once it has been determined that a given set of assertions is basically made up shit, and therefore contains no substantive knowledge about the real world,

I am not completely sure what you are referring to by "taxonomy," but, more important, I don't think you realize how self-refuting this paragraph comes across as. How has it "been determined that a given set of assertions is basically made up shit, and therefore contains no substantive knowledge about the real world?" Is that something you know a priori? Or a posteriori? Are you 100% certain that it's made up shit or is there some chance, no matter how small (say 10^-40), that the apparently made up shit could be true? If there is any chance at all, no matter how small, that the apparently made up shit could be true (why wouldn't there be?), then you need to deal with probabilities.

Note also, BTW, that if you believe theism is "made up shit," then by definition and on your own admission, you not only lack the belief that God exists, but you also hold the positive belief that God does not exist.

Calilasseia wrote:do we really need to engage in navel gazing with respect to the taxonomic position of one brand of made up shit against another?


I understand you think it's "navel gazing." I think it's the logically correct way to approach these issues. If you find it boring, that's fine. I'm not claiming you have to do anything. But if you are going to claim that all supernatural claims are equally implausible, then you need to be able to back that up and deal with objections that you consider "navel gazing."