On May 23, 10:58=A0pm, hru...@[EMAIL PROTECTED]
(Herman Rubin) wrote:
> In article
<9b361894-218c-4bcc-9e22-08811acf0...@[EMAIL PROTECTED]
>,
> > illywhacker =A0<illywac...@[EMAIL PROTECTED]
> wrote:
> >On May 22, 8:41=3DA0pm, hru...@[EMAIL PROTECTED]
(Herman Rubin)
wrote:=
> >> In article
<f6faca8c-0ac3-424e-9986-557f8b817...@[EMAIL PROTECTED]
> >com>,
> >> illywhacker =3DA0<illywac...@[EMAIL PROTECTED]
> wrote:
> >> >On May 2, 5:22=3D3DA0pm, hru...@[EMAIL PROTECTED]
(Herman Rubin)
wr=
ote:
> >> >> In article
<30309611.1209672492968.JavaMail.jaka...@[EMAIL PROTECTED]
> >org=3D3D
> >> >>,
> >> >> Luis A. Afonso <lic...@[EMAIL PROTECTED]
> wrote:
> >> =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0
=3DA0=
.................
> >> >> Just as length, mass, charge, energy exist, so does
> >> >> probability.
> >> >> Now the Kolmogorov Axioms are how we believe probability
> >> >> behaves, just as the other objects named above have
> >> >> axiomatic properties. =3D3DA0We think we understand the other
> >> >> properties of the real world well, because we can measure
> >> >> them well, while the properties of probability are such
> >> >> that it cannot be measured well.
> >> >> We are stuck with that, and therefore often cannot be
> >> >> that sure that our action is the correct one to take.
> >> >> We cannot change that, so we must accept it.
> >> >How can probability be a property of the world (as opposed to a
> >> >description of our knowledge of the world), when it can change with
> >> >the knowledge of the observer, although the world (apart from the
> >> >knowledge of the observer) has not changed? In addition, as you
note,
> >> >it cannot be measured.
> >> What is changing is conditional probability, and our
> >> knowledge of probability, just as our knowledge of other
> >> properties of nature change. =3DA0Our observation of events
> >> allows us to use conditional probability, and one can
> >> also combine "belief probability" with this.
> >You seem to be admitting that conditional probabilities are not
> >empirical properties of the world, whereas probabiltiies that are not
> >conditioned on anything are. So what would a probability conditioned
> >on nothing be? What operational, empirical meaning does this idea
> >have? None. All probabilities are conditional on something.
>
> Unconditional probabilities are conditioned on no
> information.
>
> >Let me repeat my questions, which you have ignored. How can
> >probability be a property of the world (as opposed to a description of
> >our knowledge of the world), when it can change with a change in the
> >knowledge of the observer, while the world (apart from the knowledge
> >of the observer) has not changed? If I learn a new fact, your mass
> >does not change, but the probability I ascribe to it might.
>
> You have it correct; you are not willing to admit it.
>
> >In addition, as you note, probability cannot be measured. Where are
> >the physicists measuring probability?
>
> A physicist does not measure probability, but estimates it.
>
> This is the case with other things as well; they are estimated.
>
> =A0 =A0 =A0 =A0 If it were a physical quantity,
>
> >one would expect to have probability meters. Where are they? If I toss
> >a coin, of which part of the world is the probability a property?
>
> One does not observe a physical quantity, or even a
> fact, although these can be good approximations. =A0What
> one observes is an attempted measurement, filtered
> through quantum effects. =A0With a theory about how
> the probabilities of the observations given aspects
> about the unknown state of nature, one can then do
> inference on that state, which includes the original
> probability distribution.
Oh please Herman! Quantum effects! The last refuge of the scoundrel. I
know more about quantum effects than you, and they have nothing to do
with this issue. For one thing, quantum amplitudes are not
probabilities. This is the whole point.
You still have not answered the following.
If I learn a new fact, your mass does not change, but the probability
I ascribe to it might.
If I toss a coin, of which part of the world is the probability a
property?
A physicist measures a mass. You can call it estimating if you want,
but we know what it means. Now give me an example of a physicist
'estimating a probability'. Remember, it must be conditioned on 'no
information', whatever that means, or it ceases to be a property of
the world according to you. How a physicist can even make a
measurement if he or she possesses no information is beyond me.
Give me an example of a probability conditioned on no information.
One does not 'observe an attempted measurement'. This would mean
looking at someone trying to measure something (and failing, in
standard English usage). Rather, one makes a measurement and observes
the outcome. No new usages are needed to describe this process. Our
knowledge of the underlying system given this measurement is described
by a probability, of course, and measurements can be subtle and tricky
things. So what?
The point of view you are espousing is not false in any empirical
sense. It is merely useless, whereas the point of view I am espousing
is useful. The same distinction exists between the assertions that the
world is deterministic and that it is stochastic. This is not an
empirical question. Rather, supposing it is stochastic is less useful
as a point of view. That is all. You need more familiarity with
science, not with mathematics.
illywhacker;
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