From: gts (gts@optexinc.com)
Date: Wed Sep 04 2002 - 08:08:38 MDT
Dan Fabulich wrote:
> <ahem> I selected a frequentist example just to make the distinction
> clearer. But we can wage this argument in Bayesian terms as
> well, if you like.
Great. Let's try.
I wrote the following:
>> A person with a 1/32768 chance of dying is not "exempt from death."
You replied:
> If you concede that there is a *fact* of the matter
> as to whether you are exempt from death or are not exempt
> from death, then the Bayesian probability of your immortality
> is merely a measure of your subjective confidence in your
> beliefs about the fact.
That is not something I am willing to concede. I have no idea whether I
am exempt from death, and at present there is no technology known to me
that would ensure my immortality regardless of my beliefs about the
subject (which is not to say such technologies don't exist).
> If you *don't* concede that there's a fact of the matter
> as to whether you are immortal or not, then I must concede
> that you could construct your terms in such a way that
> immortality (like absolute certainty) is unavailable.
Yes.
> 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.
I don't quite follow the rest of your argument but I will respond in any
case:
> But I see no reason to think that "immortality" is a special
> case on this interpretation; ALL "a posteriori" predicates
> would suffer from the same problems of uncertainty under this
> reading. After all, doesn't the property of being "red" imply
> that there's no chance of not being red?
Yes.
> 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.
> 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".
> 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.
> 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."
-gts
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