Re: No link between mobile phones and tumours - study

["Fritz A. Seiler" <faseiler@NMIA.COM>]

Dear Dov,



	John Moulder and I had a fruitful discussion on that subject off-list. 

The problem really is what causation means. I am a physicist and thus

for me there is nothing more comprehensive than the mechanism, and that

means the complete etiology of the health effect. The question is what

is sufficient to claim that we understand the "causation" of a health

effect sufficiently well to do a risk calculation. The etiology of

cancer, for instance, is not really known well enough to claim that we

know what its full chain of causation is.  The Moolgavkar model is a

very good partial model of causation, but it stops after the

transformation of the second population to the third type of transformed

cell, i.e., short of a clinical cancer.  I use the Moolgavkar model

myself, but I am aware of the leap of faith involved in going from cell

type C<3> to a clinical cancer.

	To paraphrase what John and I agreed on as a substitute for a good case

of "causation". We require three legs for a causation argument:

  - positive epidemiological and clinical studies,

  - positive biological studies (cell, animal, human volunteers),

  - theoretical support (pharmacology/toxicology in the case of

chemicals, 

    and biophysics in the case of physical agents).

We claim that you need strong evidence in at least one leg, and no

contradiction in the other legs, to successfully argue for "causation".  



Best regards,



Fritz





************************



Fritz A. Seiler, Ph. D.

President

Sigma Five Consulting

P.O. Box 1709

Los Lunas, NM 87031, USA

Tel.   505-866-5193

Fax.  505-866-5197

e-mail: faseiler@nmia.com



***********************





Dov Brickner wrote:

> 

> >

> > Two points:   1. Correlation does not imply Causation!

> >               2. Causation requires a Mechanism!

> 

> Causation requiers more than mechanism. Causation requiers Good and

> repeated correlation, a dose -effect relationship is desireable, AND a

> plausible mechanism .

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