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This is just one of my musings about philosophy that is, doubtless, more interesting to me than to others ... but it's my blog! Feel free to spare your glazed-overed eyes.

There is a common argument for atheism that runs like this:

The parts of the above in brackets are intended to indicate that this argument is stated with varying degrees of certainty and toward various conclusions.

Now, I'm an Apathetic Agnostic ("We don't know and we don't care") . Among the "tenets" of apathetic agnosticism (if we cared enough to actually hold to something as tiring as a tenet) is:

In short, I agree with the claim that there is no apparent purpose to the universe but I disagree with the atheistic conclusion from that appearance. Okay, you may be asking yourself, but why bring it up? Well it turns out that I, at least, have a purpose and that is to discuss a point made by Elliott Sober, one of the best philosophers of science at work today, in his excellent but difficult (for me, at least) book, Evidence and Evolution: The Logic Behind the Science.

The atheist argument above actually takes the form of what Sober calls a "probabilistic modus tollens." The standard modus tollens is a rule of deductive reasoning as follows:

If H, then O
not O
????????????
not H

... which reads: if the hypothesis H entails the observation O, and O turns out to be false, then it follows that H is false. The sticking point is that "entails." In order for the above syllogism to be valid, it must be certain that, if H is true, you will make the observation O.

But science does not work like that. Science is fallibilistic and incomplete. That is the basis of the common saying "the absence of evidence is not evidence of absence." Otherwise, it would follow, for example, that the universe was not expanding until Edwin Hubble made his observations of stellar redshifts, since, until then, there was an absence of evidence for expansion.

This aspect of science means that the very best that the atheistic argument can state is:

Pr(O \ H) is very high
not O
????????????????????
not H

... which reads: if the hypothesis H says that O will very probably be true, and the scientific observation, O, is not made, then H is false [or, at least, very improbable and, therefore, should be rejected]. Sober explains the problem:

What is more, it does not follow that the failure to observe O can even be considered as evidence against H. Converting the probabilistic modus tollens to an "evidential probabilistic modus tollens," the argument now takes the form:

Pr(O \ H) is very high
not O
???????????????????????????
not O is evidence against H

... which reads: if the hypothesis H says that O will very probably be true, and the scientific observation, O, is not made, then that failure is evidence against H. But consider the counterexample Sober gives:

In short, in order to make a claim about the evidential value of the failure to make an observation, you need to do more than test the hypothesis against its negation.

Simply saying that you are testing a "purposeful" universe against a "purposeless" one doesn't help because you merely run up against the Duhem?Quine thesis, which holds that any test of a hypothesis necessarily entails auxiliary hypotheses that, unless they are also being tested, may affect the outcome -- such as the number of urns involved and the percentage of white balls they hold. In other words, before the absence of scientific evidence of purpose could justify an evidentiary claim, there would have to be a comprehensive account, including all relevant auxiliary hypotheses, of what a purposeful universe would look like. Besides the difficulty, if not impossibility, of constructing such a complete theory of purpose, the very comprehensiveness of the theory would prevent the result from constituting a general refutation of purpose. The evidence of absence would only apply to the now narrow collection of hypotheses and auxiliary hypotheses.

In fact, the atheist argument runs up against the very problem that the IDers face when they claim to demonstrate disembodied "design." Without knowledge of the motives and abilities of the purported "designer" or "purposer," there is no way to differentiate the action (or non-action) of such a being from our state of ignorance.

There is much more that can be said on the subject and Sober exhaustively exposes the philosophical weaknesses of ID, much of which applies as well to this argument for atheism. But it is only fair to ask why, if I think that the argument fails logically and scientifically, do I then accept the lack of apparent purpose in the universe as any basis for agnosticism? For one thing, the question that the lack of evidence bears on is (perhaps subtlety) different. Instead of considering whether there is, in fact, purpose behind the universe, the issue is whether whatever purpose-giver there may be is interested in humans knowing and reacting with that purpose. Given that any being capable of imparting purpose to an entire universe is presumably capable of making its existence and intentions known in unambiguous ways, a tentative conclusion that any such being is uninterested in human participation is, if not logically or scientifically rigorous, at least not unreasonable.

And that leads to my final point. Science is not an appropriate tool to determine matters that are, ultimately, nothing more than personal preferences as to how to approach life. Certainly, science's methods and results can be taken into account by anyone considering those preferences but, in the end, our weltanschauung is made up of a bundle of emotions, attitudes learned in childhood and unconscious value judgments with, at most, only partial imput by reason. Furthermore, science delivers information on what is, not what ought to be. Any assertion that we should determine our values and preferences by scientific rationalism is not, itself, a result of the scientific method, making the claim circular and self-defeating.

When it comes to values, we're on our own.
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