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Sep 17, 2011           

Probability and Harold Jeffreys


The true logic of the world is in the calculus of probabilities
 -- James Clerk Maxwell

I am not well, so I only give some references that I recently found that interest me and that may interest others (who read Nederlog), and that relate to probability and scientific inference, two subjects I have been much concerned with.

First, here are three general and fairly large files on probability that are quite useful as surveys

Figures from the history of probablity and statistics

This is by John Aldrich who teaches economy at the University of Southampton, and it is well done and extensive, as are several other html-files he maintains such as

Set Theory & Logic

There is quite a lot more there by him, including some on Ricardo's theory of value, that may interest anyone who liked Sraffa's "Production of Commodities by Means of Commodities".

Back to probability theory: Here is another good survey

Probability, Logic and Probability Logic

to which I owe my opening quotation (that I knew before, but don't always have ready on the tip of my tongue). This is by Alan Hájek, and quite good.

Finally, to Harold Jeffreys, which led to the above, since I owe and like his

Scientific Inference

that now is available on the Internet Archive (which is an excellent site and organization, except that they insist on flashing unreadable thumbnail pictures of the excellent books they provide, which I find quite irritating, perhaps because of my ME/CFS) and which also has the starting chapter on Google:

Chapter I - Logic and scientific inference

That starts with the following epigraph (not postmodernistic!)

The Master said, Yu, shall I tell you what knowledge is? When you know a thing, to know that you know it, and when you do not know what a thing is, to recognize that you do not know it. That is knowledge.
    -- Analects of Confucius (Waley's translation)

If you are interested in the subject at all, read Chapter I!

This also leads me back to John Aldrich's fine site, who also has a lot on Sir Harold (who was knighted due to his scientific excellence):

Harold Jeffreys as statistician

In case you don't know who he was, here is a link to his biography at Mac Tutor, followed by links to two extracts, from the same source (of biographical information about many mathematicians):

Harold Jeffreys
Harold Jeffreys: From Preface to Scientific Inference
Harold Jeffreys: On logic and scientific inference

Finally, I was also pleased to find this is on line:

Harold Jeffreys and Bertha Swirles Jeffreys:
Methods of mathematical physics
(pdf, 40 MB)

This I have read in part, in the 1970ies, from the university library, so I am pleased it is now available as pdf. Incidentally, the writers were husband and wife, and were both excellent mathematicians.

As to mathematics: It may be that the mathematical style of the Jeffreys seems a bit outdated. For a refresher course on it, provided you do know basic mathematics and calculus, there is now happily on line

G.H. Hardy: A course of pure mathematics (1921-edition)

There are later editions (I have one from 1937), and the book seems also still in print, and is better than most on the subject, if not the latest nor in the latest style of presenting mathematics (with lots more set theory - or set-theoretical notation - than Hardy thought necessary.)

Finally, I do hope to see Harold Jeffreys' Theory of Probability on line, but so far it seems not to be there, which is unfortunate, because it is one of the classics of Bayesian reasoning:

Bayesian inference|
Bayesian probability

These are Wikipedia entries. A recent good book on the subject is

Scientific Reasoning: The Bayesian Approach

This links to a part of the 2nd edition, explaining what it is all aboout, and is used for teaching in the US. I have the first edition on paper, and there is now a third edition in print, and it seems to be also completely available in pdf for some.

Have fun!

And in case you won't, with this manner of material or these kinds of subjects: In any case, this is one of the great things about the internet - that it is so very much easier to provide one's own education, and to find decent editions of classical texts.

This is also true if your tastes and preferences are quite different from mine: If you have the brains and the time and the interest to do so, you can much better read up on things and develop your own talents in your own way than it was for me, when I was 20, in 1970: Books were expensive, hard to get, slow to arrive, not easy to copy if on loan, a.s.o.

So there is progress, even amongst regress and crisis.


P.S. Corrections, if any are necessary, have to be made later.

Incidentally... my deep abhorrence and total disdain for the sick sadistic psychiatric freak professor Simon Wessely - the man who insists on totally fallacious, sadistic, pseudoscientific grounds that I and millions of others are suffering from "dysfunctional belief systems" and are thinking ourselves ill is based on my longstanding knowledge of material such as the above, next to what's listed here:

I really think a man with ideas and practices like Wessely shows that psychiatry is very fit to be ousted from science as dangerous and harmful pseudoscience that is bound to give medicine and medical doctors who are not psychiatrists a deserved bad reputation as long as they allow this manner of frauds to present themselves as if they are medical scientists.


As to ME/CFS (that I prefer to call ME):

1.  Anthony Komaroff Ten discoveries about the biology of CFS (pdf)
3.  Hillary Johnson The Why
4.  Consensus of M.D.s Canadian Consensus Government Report on ME (pdf)
5.  Eleanor Stein Clinical Guidelines for Psychiatrists (pdf)
6.  William Clifford The Ethics of Belief
7.  Paul Lutus

Is Psychology a Science?

8.  Malcolm Hooper Magical Medicine (pdf)
 Maarten Maartensz
ME in Amsterdam - surviving in Amsterdam with ME (Dutch)
 Maarten Maartensz Myalgic Encephalomyelitis

Short descriptions of the above:                

1. Ten reasons why ME/CFS is a real disease by a professor of medicine of Harvard.
2. Long essay by a professor emeritus of medical chemistry about maltreatment of ME.
3. Explanation of what's happening around ME by an investigative journalist.
4. Report to Canadian Government on ME, by many medical experts.
5. Advice to psychiatrist by a psychiatrist who understands ME is an organic disease
6. English mathematical genius on one's responsibilities in the matter of one's beliefs:

7. A space- and computer-scientist takes a look at psychology.
8. Malcolm Hooper puts things together status 2010.
9. I tell my story of surviving (so far) in Amsterdam/ with ME.
10. The directory on my site about ME.

See also: ME -Documentation and ME - Resources
The last has many files, all on my site to keep them accessible.

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