When
faced with miraculous testimonies, skeptics often cite the mantra
'extraordinary
claims require extraordinary evidence'. In turn believers charge skeptics of being overly skeptical, and arbitrarily setting a higher bar for claims to the supernatural. And, often times, they are right. If
you ask most skeptics why
extraordinary claims require extraordinary evidence, or what
it is to be an extraordinary claim, they usually aren't able to
explain themselves very well. But, I think, there is some truth to
this mantra, and it can be fleshed out in a mathematically rigorous
way. Enter Baye's theorem, which states:
Pr(A|B) = Pr(B|A) * Pr(A) / Pr(B)
Once you're aware of it, all the pieces fall into place. An
extraordinary claim is simply one with a very low prior probability.
Extraordinary evidence is simply evidence that is very strong, having
a very high conditional probability. It's
almost self-evident that very improbable events require very strong
evidence before we can reasonably accept them, but Baye's theorem
shows us why. Suppose A is an extraordinary claim (having very low
prior probability), and B is an established fact which isn't
incredibly probable or improbable. The ratio Pr(A) / Pr(B) is going
to be very close to zero, which will cause Pr(A|B) to be a very small
fraction of Pr(B|A). If Pr(B|A) isn't incredibly large to begin with,
the fact that B is evidence for A is going to be practically
insignificant.
Now
let's turn our attention to a particular miracle—probably being the most influential—the resurrection of
Jesus of Nazareth. I'll admit, there is interesting
evidence for this miracle. It's enough, at least, to catch ones
attention. But rationalize belief? I'm not so sure. The problem is
precisely that extraordinary claims require extraordinary evidence; while the evidence of Jesus' resurrection seems fairly strong (if
similarly strong evidence was presented for a more mundane claim, you
would surely be convinced), it doesn't seem strong enough to overwhelm the
initial implausibility of the claim.
Think
about the sort of claim being made, that someone rose from the dead
after three days of rot and decay. In all of our experience with
death, people tend to stay dead. Even under ideal conditions where
the body has been frozen and there is a team of doctors standing by, resurrection is still incredibly difficult.
But in all of our experience with death, never have we observed
someone coming back from the dead after three days (excluding this
one case). In fact, over a hundred thousand people die every day, and
we never see
anyone raised as Jesus is said to have been. It then seems we must
think that resurrection after three days is really
really really
improbable.
Apologists
will agree to an extent, but say drawing conclusions about Jesus'
resurrection isn't fair. This is, after all, supposed to be a
miracle,
which suggests it occurred by supernatural means. But even
here still, one can assume God exists (and has the power to raise the
dead), and still point out that it happens (if at all) at a frequency of near zero.
Even under the assumption of classical theism, a resurrection of this sort seems incredibly improbable. Apologists will retort
that Jesus was a special case; he was, after all, the son of God. But
herein lies the problem. If one must assume the existence of a god
that wants to raise Jesus in particular, but not anyone else, then
they're practically assuming the Christian
god. There isn't any other god we know of that would have special
reason to bring back this one particular Palestinian, two
thousand years ago.
And
this is fine for them to assume, given that Christianity itself is a
fair assumption. But what isn't
permissible is them using the supposed fact that Jesus rose from the
dead as evidence
for Christianity as apologists typically do. They are committing a
sort of question begging fallacy. They want to argue that Jesus'
resurrection is evidence for the Christian god, when they must
presuppose something very much like
the Christian god exists to even establish that Jesus rose from the
dead in the first place. But if that's the case, then the fact that
Jesus rose from the dead offers nearly nothing in favour of
Christianity. It can't raise
the probability of Christianity significantly more than what is
already granted.
All this is to say that there is still a wide chasm between establishing classical theism, and establishing Christian theism. And, it can only be crossed by showing that the god of classical theism would probably have motive to raise Jesus, in particular, from the dead. But this in of itself seems just as difficult to defend as anything else and, as such, it seems the prospect of defending Christian theism by use of an argument from miracles is bleak.
All this is to say that there is still a wide chasm between establishing classical theism, and establishing Christian theism. And, it can only be crossed by showing that the god of classical theism would probably have motive to raise Jesus, in particular, from the dead. But this in of itself seems just as difficult to defend as anything else and, as such, it seems the prospect of defending Christian theism by use of an argument from miracles is bleak.