Jef,
I understand it, Jef. But do you? The principle of indifference
is not derived from or implied in any way by De Finetti
coherency. De Finetti had no use for the idea. Neither do I.
That's like saying you have no use for [the idea that] a balance scale
reads zero when both pans are empty.
Here is something Frank P. Ramsey wrote about the principle of
indifference after discovering (independently of Bruno De Finetti) that
coherence was sufficient to derive the axioms of probability:
"Secondly, the Principle of Indifference can now be altogether dispensed
with; we do not regard it as
belonging to formal logic to say what should be a man's expectation of
drawing a white or a black
ball from an urn; his original expectations may within the limits of
consistency be any he likes; all
we have to point out is that if he has certain expectations he is bound in
consistency to have certain
others. This is simply bringing probability into line with ordinary formal
logic, which does not
criticize premisses but merely declares that certain conclusions are the
only ones consistent with
them. To be able to turn the Principle of Indifference out of formal logic
is a great advantage; for it
is fairly clearly impossible to lay down purely logical conditions for its
validity, as is attempted by
Mr Keynes."
-F.P. Ramsey (1926) "Truth and Probability"
Ramsey was a great genius, in my opinion. I suggest you read his paper
above. It's available on the net if you look for it. I provided a link in
some earlier message here.
-gts
-----
This list is sponsored by AGIRI: http://www.agiri.org/email
To unsubscribe or change your options, please go to:
http://v2.listbox.com/member/?list_id=303
