Well, I should qualify that. The most typical response is to simply ignore the point. But among those who do actually try to come to terms with it, the almost universal response is to begin to twitch, then start uttering blatant fallacies, and then, in the final stages, to repeat themselves over and over until finally they have rendered themselves completely absurd.
In the case of our own Singring (and we speak of him with affection, since he has do so much to help us illustrate our point here), we have someone who perfectly encapsulates all that can be said of those who have tried to come to terms with what has come to be known in philosophy as the "problem of induction," articulated by the 18th century philosopher David Hume.
Let's review the problem for just a moment, just to get it clear in our minds. Here's what can be considered rational--and this was Hume's point in the Enquiry Concerning Human Understanding, the book which articulates the problem with induction:
Something is rational if it is characterized either by inductive or a deductive inference.
A deductive argument runs something like this:
All men are mortalIt begins with a universal statement ("All men are mortal") and ends in a more particular statement ("Socrates is mortal"). Induction goes the other direction. It begins in particular observations and ends in a universal statement:
Socrates is a man
Therefore, Socrates is mortal
On every past day, the sun has risen in the morningThe issue of induction arises because of the second premise, which is the same in every inductive argument: "The future will alwasy be like the past." Hume asks, how can we justify that premise, since it does not intuitively follow from the first?
The future will always be like the past
Therefore, in every future day, the sun will rise in the morning
As to past Experience, it can be allowed to give direct and certain information of those precise objects only, and that precise period of time, which fell under its cognizance: but why this experience should be extended to future times, and to other objects, which for aught we know, may be only in appearance similar; this is the main question on which I would insist. The bread, which I formerly eat, nourished me; that is, a body of such sensible qualities was, at that time, endued with such secret powers: but does it follow, that other bread must also nourish me at another time, and that like sensible qualities must always be attended with like secret powers? The consequence seems nowise necessary. At least, it must be acknowledged that there is here a consequence drawn by the mind; that there is a certain step taken; a process of thought, and an inference, which wants to be explained. These two propositions are far from being the same: I have found that such an object has always been attended with such an effect, and I foresee, that other objects, which are, in appearance, similar, will be attended with similar effects. I shall allow, if you please, that the one proposition may justly be inferred from the other: I know, in fact, that it always is inferred. But if you insist that the inference is made by a chain of reasoning, I desire you to produce that reasoning. The connexion between these propositions is not intuitive. There is required a medium, which may enable the mind to draw such an inference, if indeed it be drawn by reasoning and argument. What that medium is, I must confess, passes my comprehension; and it is incumbent on those to produce it, who assert that it really exists, and is the origin of all our conclusions concerning matter of fact. (Enquiry Concerning Human Understanding, Section IV, Part II)How do you get from one to the other, or justify the second premise at all? These are the only two kinds of rational procedures that exist. But if you are arguing for the rationality of induction, then you can't use induction to do it, since that would be circular. Of course that hasn't stopped Singring from doing it repeatedly, and just repeating a circular argument over and over doesn't make it any less circular. That procedure is circular and therefore irrational. You can't appeal to induction to justify induction. As Hume says:
It is impossible, therefore, that any arguments from experience can prove this resemblance of the past to the future; since all these arguments are founded on the supposition of that resemblance. (Enquiry, Section IV, Part II)So the only thing left is deduction, but you can't justify induction through deduction either, since contracting the conclusion of an inductive argument does not lead to the contradiction of either of the premises (which must happen if the argument is deductively valid).
Since neither deduction nor induction can be used to justify induction, and since no other rational procedure exists, induction is not rationally justifiable. Now this doesn't mean that it shouldn't be used or that we shouldn't accept its conclusions. Our Singring jumped to the conclusion that I was saying that, but I did not say that. Although induction cannot be justified rationally, it is justified intuitively: by custom and tradition--the very things the scientistically-minded claim to spurn.
The problem of induction posed by Hume has never been resolved, and the only attempt that even makes any sense is that by Karl Popper. But Popper doesn't really resolve the dilemma, he tries to do an end run and say that science doesn't really use induction in the first place. Not a lot of people have been convinced.
I was arguing that the fundamental assumptions of science--induction and causation--were not themselves rationally justifiable in order to point up one of the absurdities of the rationalist pretensions of people like Jerry Coyne: the claim that science is "rational" and religion (and, apparently philosophy) is not.
And, as if to prove my point, people like Singring come along and try to claim that we know the future will always be like the past because the future has always been like the past in the past. In other words, trying to prove induction by appealing to induction. Induction makes sense, but atheists like Singring think it's because it's based on reason, when, in fact, it's not.
I can see why Singring has tied himself up in such complex knots to avoid the obvious conclusion. He and his fellow scientific atheists are in a pickle: either they have to admit that the method science uses is based on a rationally unjustifiable premise and reject it because it's based on faith, or they have to accept it but admit that it is based on custom and tradition, those hoary old concepts championed by the feeble-minded.
Why is it that we religious people, who aren't rational, can figure this out, but scientific atheists, the rational ones, are completely clueless (or simply fudging)?
Just keep repeating to yourselves: "Science is rational but religion is not. Science is rational but religion is not. Science is rational but religion is not ..." It's bound to be true if you repeat it enough times.