From: Dan Fabulich (dfabulich@warpmail.net)
Date: Wed Sep 04 2002 - 11:06:04 MDT
gts wrote:
> > For example, you might be the sort of Bayesian who thinks
> > that subjective confidence is all there is; that there is
> > no deeper probability/fact to know about. In that case,
> > then you might think that immortality means 100% subjective
> > confidence in your eternal lifespan, which is obviously
> > unattainable.
>
> I'm not convinced that such 100% subjective confidence is not
> attainable. If you show me a 100% reliable technology for ensuring my
> immortality then I will feel 100% confident that my immortality is
> ensured if I use the technology.
On that point: too bad. 100% subjective confidence is not attainable
about a posteriori predicates. You can get it for analytic a priori
predicates (i.e. logical tautologies), but that's it.
You'll never get 100% confidence about *anything in the world*, say
nothing of immortality.
> > Doesn't it follow from the fact that I'm twenty-three
> > years old that there is no chance that I am younger than this?
>
> Yes.
>
> > But how could I call myself
> > "twenty-three" if there's a chance that I'm not twenty-three?
>
> If you are 23 then there is no chance that you are not. Your birth
> certificate is sufficient evidence to settle the matter.
Excuse me? Birth certificates can be forged. What's the chance that mine
isn't? It's surely not 0%. I can never have 100% subjective confidence
in my birth date, though my confidence IS quite high. Heck, I doubt it's
even higher than 32767/32768, 99.9969%.
> > If you don't automatically concede to arguments of this kind
> > in the case of mundane a posteriori predicates like
> > "is red" and "is twenty-three years old", then I should
> > hardly see why you'd let them go through in the
> > case of "is immortal."
>
> I'm not clear about the meaning of your reference to "arguments of this
> kind".
Arguments of this kind are: "You cannot be 100% certain of X, so you are
not justified in your claim that X." Where X is, as I argued earlier, any
a posteriori predicate about the world that can't be guessed by pure
logic and no evidence.
> > So if the ultra-slim chance that I'm not
> > twenty-three doesn't block me from correctly saying "I'm
> > twenty-three", then the ultra-slim chance that I'm not
> > immortal shouldn't block me from
> > concluding "I'm immortal."
>
> According to the empirical evidence (your birth certificate, your
> hospital records, etc) there is no ultra-slim chance that you are not
> 23.
Sure, according to the evidence, but the evidence might be false!
Perhaps my parents had conceived me before their marriage and wished to
conceal that fact. If so, they might have had my birth certificate
forged. I'm pretty sure that's not the case, but I can never know for
sure.
> > Or what about the logical negation of immortality?
> > Why does the fact that there's a probability involved make
> > it incorrect to say that you're immortal without making it
> > incorrect to say that you're mortal?
>
> That may be a good point, however I am not questioning my mortality. I
> am questioning my immortality. I am testing the truth value of the
> statement: "I can in principle be immortal."
Actually, I'm not so ready to let the point drop this easily. If you
can't say that you're immortal because you don't have 100% subjective
confidence, you can't say that you're mortal either; you don't have 100%
subjective confidence in that. In that case, as I believe the saying
goes, of which we cannot speak, we must remain silent.
-Dan
-unless you love someone-
-nothing else makes any sense-
e.e. cummings
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