hypothesis, model, theory, Fleury

I had a few discussions about the use of these terms, in general and in connexion with the present case, and I would like to avoid explaining the use I make of them for each person interested by. I’ll try to pack my opinion in a single post.


An « hypothesis » is a statement restricted to what can be formulated to describe a phenomenon prior to any experimentation. When communicating it is always preferable to associate to formulated hypotheses the tests one could/will use to test them, the expected results and what would validate or invalidate them.

A « model » is an hypothesis that was proven valid, experimentally, in a limited set of situations and need further testing to be considered as valid. Often associated to a mathematical construct allowing predictions that should be verified experimentally.

A « theory » is an hypothesis (or set of related hypotheses) that was (were) thoroughly proven valid through experimentation.


A scientific communication, non supported by experimental data, but associated with a set of experiment to be conducted to allow validation, I call a « working hypothesis ».

A scientific communication, non supported by experimental data and non presenting the way it must/will be tested, I call simply « hypothesis ».

A scientific communication supported partially by experimental data and predictions, I call a « model », implicitly a « working model ».


Thus, I think that the use of the term « model » for the hypothesis discussed here is inappropriate, as the author admitted that he didn’t experimented to test it. Neither offered what tests he planned to validate it.

It may be useful to initiate discussions, but certainly not to support a theory, not a scientific one anyway. My main critic to Fleury is that he use this reference as a peer reviewed element in support of his theory, which include a few other hypotheses, none of them validated (as far as I know, but it seems that there are unpublished segments) and some in clear opposition with well established scientific theories, at least genetics & evolution.

Per se, I don’t think that his theory present a particular interest, and I wouldn’t be personally interested by his claims. My interest was pulled by the use made by Jean Staune of the UIP. And it was conserved by Fleury’s continuous pressure to present it as possibly useful to support his theory.
Jamie Davies wrote: « I know of no area of biology in which purely theoretical hypotheses and models can be considered firm foundations for anything, until they have been validated experimentally. »
I’m in the same case.


Now, each segment of my review access a single point that must be validated. It seems that it is not clear what evidence should be produced in face of each assumption to substantiate it and connect it to experimental (physical) reality. For example, there was a confusion between « cellular flows » as experimentally visible and « stream lines » of a mathematical construct.
I’ll try to do better from now on, associating to each point what evidence could be useful, what techniques may be used (if I know about them), reference a few papers describing similar works, and what results could validate the assumptions made.
I will add a list at my conclusive remarks, including #1 and #2.


Please, keep the comments in relation with the post’s subject. I hate editing them but I will deleted whatever I consider inappropriate. Already started to do so. This is not your personal free speech space, if you need one clic here and follow the instructions, it’s free of charges. For this post, comments are closed, trackbacks open.

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