function has been ontologized heavily already - but what really is it? He has some alternate definitions for both function and role: definitions which are simple, clear, and (critically) applicable. - Allyson Lister

Alternate BF definition: A biological function is a RE where the homologous structures of individuals of closely related or the same species bear this same biological function. - Allyson Lister

What distinguishes a biological function from an artifactual function? It is the bearer that distinguishes it, not the process. - Allyson Lister

The function definition seems quite circular. - Robert Hoehndorf

Function and Role should be defined subclasses. - Allyson Lister

@Robert I think Phil has an answer for that - ask him in the question section:) - Allyson Lister

The definitions seek not to change the current usage but just formalise that usage. - Allyson Lister

Blog post: http://themindwobbles.wordpress.com/2009... - Allyson Lister

It's also posssible to unwind the definition, but it makes the definition longer; might be easier to take it out if it causes trouble - Phil Lord

@Phil: do you take every process that occurs in an entity and in homologous closely related ones as a realization of a function? I.e., my heart makes thumping noises, and so does the heart of every closely related organism. Then, would you say that the heart's function is to make thumping noises? - Robert Hoehndorf

@Robert there are three answers to that -- the first is to argue that "thumping noises" is not end-directed. This is a fudge though; I don't know how to generate an assay which we can used to test end-directed. The next is to say "yes" but distinguish primary/secondary function where the distinction is "because the biologists care about it". The third was really presented in a talk by Hoehndorf et al. So. it's a problem for my definition, but no more of a problem than the current definition. - Phil Lord