On 3/13/2012 4:00 AM, Warp wrote:
>    I have been pondering about this, and I can't find a definitive, easy
> answer. I was wondering if I could get some ideas here.
>
>    Skepticism is often defined as "not accepting claims at face value,
> without proper evidence". However, what makes evidence "proper" and
> "valid"? The answer to that question isn't as easy as one might hastily
> think.
>
>    One could argue that valid, proper evidence must be testable and
> verifiable. While that's certainly a necessary property of such evidence,
> it isn't sufficient.
>
>    For instance, an apologetic could argue that the existence of life is
> evidence for the existence of a god, and the existence of life is certainly
> testable and verifiable. However, the mere existence of life, while
> verifiable, isn't sufficient evidence for the existence of any god, hence
> this purported evidence is not proper. But what makes it not proper?
>
>    One could say that one reason why it's not proper is because there's a
> deductive fallacy being committed here, like:
>
>    1) God is an explanation for the existence of life.
>    2) Life certainly exists.
>    3) Therefore God exists.
>
>    This is the "affirming the consequent" fallacy. (The first proposition
> can be formulated as "if God exists, he created life".)
>
>    An even clearer case of "affirming the consequent" is that the alleged
> existence of supernatural miracles is given as evidence for the existence
> of a god. (You see this *all the time*. People will argue how miracle
> healings happen all the time, how people speak on tongues and whatever.
> And this is somehow evidence for the existence of God.) Here the fallacy
> goes like:
>
>    1) If the God of the Bible exists, he performs miracles.
>    2) Miracles do happen.
>    3) Therefore the God of the Bible exists.
>
>    (Even if we accepted the first two premises, the conclusion is incorrect.
> This is no different from "if it rains, I get wet; I'm wet; therefore it's
> raining".)
>
>    In these examples the existence of life and the alleged existence of
> miracles (even if we granted that assumption) are not valid evidence for
> the existence of a god. That's just a deductive fallacy.
>
>    However, let's compare it to something that *is* considered valid and
> proper evidence for something else, namely the theory of evolution:
>
>    Evolutionary biologists predicted the existence of fossils of a flat-headed
> fish with eyes on top somewhere in late devonian strata before they were
> found. Motivated by this prediction they searched for such fossils in
> geological strata of that age, and they found exactly that. (It was later
> named "tiktaalik".) This was a marvelous prediction of the theory of
> evolution, and a wonderful piece of evidence for its validity. Nobody
> doubts this is valid and proper evidence.
>
>    However, an apologist could argue that the same deductive fallacy is
> being committed here, namely:
>
>    1) If the theory of evolution is true, then we should find fossils of
> a flat-headed fish with eyes on top somewhere in late devonian strata.
>    2) Such fossils have been found in the correct strata.
>    3) Therefore the theory of evolution is true.
>
>    But this is the exact same "affirming the consequent" fallacy as before!
>
>    What makes the difference? Why is this evidence for evolution valid and
> proper, but eg. the existence of life or alleged miracles for the existence
> of a god isn't?

It is true that a false conclusion must have a faulty argument, but it 
is not true that a faulty argument must have a false conclusion.

We nail the fallacy in the argument with the false conclusion, because 
we know, as a consequence of the laws of logic, that if the conclusion 
of an argument is false, there must be something wrong with it, and we 
don't rest until we find it.

However, when we agree with the conclusion, we just nod our heads and 
gloss over the fallacies in the argument.  For most people, it doesn't 
matter how we get to the truth, as long as we get there.

But you're not most people.  You are setting forth the idea that yes, it 
does matter how we get to the truth, because if we don't get there in 
the right way, we don't get there at all; that in intellectual matters 
as well as physical ones, the end does not justify the means.

The answer to your dilemma is that invalid arguments prove *nothing*. 
We all clearly recognize that faulty arguments do not truly prove their 
conclusions, but sometimes fail to remember that faulty arguments do not 
disprove their conclusions, either.

However, faulty arguments do give their conclusions a bad reputation. 
Somewhere a preacher is citing Piltdown Man as proof that evolution is 
false, and somewhere an atheist is claiming that the Shroud of Turin 
disproves all Biblical claims.  This is not to say that anyone reading 
this makes these claims, or that anyone is making these specific claims, 
but like you I see the same illogic coming out of both sides of the debate.

Now to make all this useful, what do we do?

The obvious thing is to apply to our own arguments all of the critical 
rigor that we bring to bear on our opponent's arguments.  I think Jesus 
had something to say about this somewhere.

Regards,
John

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