Dear Ash,
Thanks for the kind comments regarding Dicing with Death. I am
an admirer of Hume's but not a fellow countryman. The most famous philosopher
from my country (Switzerland) is Rousseau - not a patch on Hume as a philosopher
but certainly his master as regards writing. Anyway, thanks for reminding me
about Kant. There is a Swiss connection (or should I say a bridge) in that it
was the Swiss mathematician Euler who solved the Konigsberg problem, thus inaugurating
the topic of Graph theory (not to be confused with Prussian political science
or Graf theory).
Regards
Stephen
From: Ash Paul
[mailto:[log in to unmask]]
Sent: 02 February 2011 15:15
To: Stephen Senn; [log in to unmask]
Subject: Re: Can RCT help establish causation? A philosopher's reply
Dear Stephen,
You yourself have written in your
excellent book 'Dicing with Death: Chance, Risk and Health' that your fellow
Scotsman David Hume managed the unhappy trick of seeing his masterpiece
(1739-40) die as it was born. "Never literary attempt was more
unfortunate than my Treatise of Human Nature. It fell dead-born from the press
......."
Hume himself confessed that love of literary fame was his main motivation in
writing. He also abandoned writing for a while after he failed in his
application for the Chair of Ethics and Pneumatical Philosophy at Edinburgh
University.
Immanuel Kant ultimately read the slimmed-down reworked version of his
magnum opus ' An Enquiry Concerning Human Understanding' (1748), to which he
replied in his 'Prolegomena' in 1783.
Regards,
Ash
Dr Ash Paul
Medical Director
NHS Bedfordshire
21 Kimbolton Road
Bedford
MK40 2AW
Tel no: 01234897224
Email: [log in to unmask]
From: Stephen
Senn <[log in to unmask]>
To: [log in to unmask]
Cc:
Sent: Wednesday, 2 February 2011, 11:20
Subject: Re: Can RCT help establish causation? A philosopher's reply
Littlewood said of Bertrand Russell
'He said that what Kant did, trying to answer Hume (to whom I say there is no
answer), was to invent more and more sophisticated stuff, till he could no
longer see through it and could believe it to be an answer.
Stephen
Stephen Senn
Professor of Statistics
School of Mathematics and Statistics
Direct line: +44 (0)141 330 5141
Fax: +44 (0)141 330 4814
Private Webpage: http://www.senns.demon.co.uk/home.html
University of Glasgow
15 University Gardens
Glasgow G12 8QW
The University of Glasgow, charity number SC004401
________________________________________
From: Evidence based health (EBH) [[log in to unmask]]
On Behalf Of Ash Paul [[log in to unmask]]
Sent: 02 February 2011 03:30
To: [log in to unmask]
Subject: Re: Can RCT help establish causation? A philosopher's reply
Dear Ben and Jeremy,
I may be missing something obvious here in this excellent discussion, but in
relation to the philosophical discussion on this fascinating topic, while there
appears to have been mention of Hume, I can't seem to find any explicit
references to Emmanuel Kant.
In 1783, in his 'Prolegomena To Any Future Metaphysics', Kant attempted to
answer Hume's skeptical views on causality.
You can read a summary of Kant's response to Hume in the Stanford Encyclopedia
of Philosophy:
http://plato.stanford.edu/entries/kant-hume-causality/
Regards,
Ash
Dr Ash Paul
Medical Director
NHS Bedfordshire
21 Kimbolton Road
Bedford
MK40 2AW
Tel no: 01234897224
Email: [log in to unmask]<mailto:[log in to unmask]>
From: Jeremy Howick <[log in to unmask]>
To: [log in to unmask]
Cc:
Sent: Monday, 31 January 2011, 12:41
Subject: Re: Can RCT help establish causation? A philosopher's reply
Dear Jim,
You are right that technical definitions of deductive validity and proof
are, from a practical perspective, irrelevant. What we are interested in
is whether we have SUFFICIENT evidence to ACT. See attached figure I made
based on an idea that Paul developed. When the effect size outweighs the
combined effect of plausible confounders, we have sufficient evidence.
This sword, however, cuts in a way that needs to be addressed by GRADE:
when the ABSOLUTE effect size in a randomized trial is tiny (even if we
have used concealed allocation etc.), then it wouldn't take a large
confounder to 'tip the scale' and we need to question the conclusions of
the trial.
Best wishes,
Jeremy
On 31/01/2011 04:08, "Jim Walker" <[log in to unmask]<mailto:[log in to unmask]>>
wrote:
>Perhaps thinking of the problem in engineering terms (rather than
>philosophical) can be useful:
>The goal in machining parts is not perfection, but achieving acceptable
>tolerances for the part (based on its intended use).
>From this perspective, the relevant question is something like "Is the
>likelihood that this observed relationship is due to chance low enough
>that it is appropriate to act as if it were a causal relationship?"
>
>
>Then we can avoid the trap of treating RCTs as if they were
>qualitatively different from (rather than quantitatively superior to)
>other study designs. That is, a well done non-RCT study may be entirely
>adequate to prompt a change in practice (e.g., Semmelweis).
>
>Jim
>
>James M. Walker, MD, FACP
>Chief Medical Information Officer
>Geisinger Health System
>
>The best way to predict the future is to invent it.
>
- Alan Kay
>>>> Stephen Senn 01/30/11 6:48 PM >>>
>However, I don't think that it is necessary for RCTs to control for all
>confounders for valid inference to be based on them and it is precisley
>this point that I think many commentators are confused on.
>Stephen
>
>
>Stephen Senn
>
>Professor of Statistics
>School of Mathematics and Statistics
>Direct line: +44 (0)141 330 5141
>Fax: +44 (0)141 330 4814
>Private Webpage: http://www.senns.demon.co.uk/home.html
>
>University of Glasgow
>15 University Gardens
>Glasgow G12 8QW
>
>The University of Glasgow, charity number SC004401
>________________________________________
>From: Evidence based health (EBH) [[log in to unmask]<mailto:[log in to unmask]>]
>On Behalf Of Jeremy Howick [[log in to unmask]<mailto:[log in to unmask]>]
>Sent: 30 January 2011 23:20
>To: [log in to unmask]<mailto:[log in to unmask]>
>Subject: Can RCT help establish causation? A philosopher's reply
>
>Dear All,
>
>Stephen is correct that philosophers have been discussing the issue of
>how to establish scientific knowledge for centuries * if not longer *
>and it is fair to say that there is no widely accepted response to the
>problem Hume posed. (Hume famously argued that while we would be 'fools
>or madmen' to NOT accept scientific knowledge, inductive reasoning upon
>which scientific laws are base have no rational justification (for a
>simple explanation see: en.wikipedia.org/wiki/Problem_of_induction).)
>
>However, philosophers (and others) HAVE managed to provide "a
scientific
>method that allows us to LOGICALLY distinguish coincidence from
>causation". See, for example, Cartwright (2007):
>
>journals.cambridge.org/action/displayAbstract?fromPage=online&aid=1002668
>
>A simple way to put Cartwright's claim is: "if RCTs control for all
>confounders, then their conclusions about the causal properties of the
>intervention are valid".
>
>The problem, of course, is that even the best randomized trial DO NOT
>control for ALL confounders. They are better than other methods at
>ruling out confounders, but are not perfect. Hence the EBM insistence
>that we keep UP TO DATE with the latest evidence that might overturn
>previous evidence. I try to explain this clearly in my forthcoming book
>(http://www.amazon.co.uk/Philosophy-Evidence-Based-Medicine-Jeremy-Howick/
>dp/140519667X).
>
>Best wishes,
>
>Jeremy
>
>From: "[log in to unmask]<mailto:[log in to unmask]>"
>
>Reply-To: "[log in to unmask]<mailto:[log in to unmask]>"
>
>Date: Fri, 28 Jan 2011 15:06:33 +0000
>To: "[log in to unmask]<mailto:[log in to unmask]>"
>
>Subject: Can RCT help establish causation?
>
>Dear all
>I'd like to post this question to the group that I have been thinking
>about for some time... Is there a scientific method that allows us to
>LOGICALLY distinguish the cause-effect from the coincidence? David
>Hume, one of the most influential philosophers of all times, concluded
>that there is no such a method. This was before RCTs were
"invented".
>Many people have made cogent arguments that (a well done) RCT is the
>ONLY method that can allow us to draw the inferences about causation.
>Because this is not possible in the observational studies, RCTs are
>considered (all other things being equal) to provide more credible
>evidence than non-RCTs. However, some philosophers have challenged this
>supposedly unique feature of RCT- they claim that RCTs cannot (on
>theoretical and logical ground) establish the relationship between the
>cause and effect any better than non-RCTs. I would appreciate some
>thoughts from the group:
>1. Can RCT distinguish between the cause and effect vs. coincidences?
>(under which -theoretical- conditions?)
>If the answer is "no", is there any other method that can help
establish
>the cause and effect relationship?
>I believe the answer to this question is of profound relevance to EBM.
>
>Thanks
> Ben Djulbegovic