1. There are actually living cells which have partial flagella, such is the sperm cells of some eels. Thus the claim that the flagellum is useless unless complete is false
2. Evolutionary modifications can involve the removal of components as well as the addition of them, and can also involve the co-option of systems for uses other than their original ones (e.g. reptilian jawbones becoming mammalian earbones). Irreducibly complex systems can evolve by either of these routes.
(Incidentally, it's easy to show that evolution of irreducible complexity is possible - simulators such as 'tierra' often evolve 'organisms' of which no part can be deleted from 'organisms' which do not have this trait.)—unsigned comment by unknown (talk • contribs)
The trouble of proof
Showing that some particular biological entity is irreducibly complex is indeed a fast track to discrediting Darwin's theory, as he freely admits, and correctly so. I fear that our argument however needs some refinement yet. We need to be able to show or prove that something is irreducibly complex, we can't just suppose it, no matter how sure we are. Just because we cannot imagine a use for something that is a fraction of its proposed former self, does not mean that it hasn't one. In the case of the flagellum, we would need to identify all possible previous forms of it that would allow evolution to produce it. Then we would have to demostrate or simulate each one in every circumstance that it might have a use (good luck enumerating the circumstances, impossible.). So I think we need to find a simpler example than the flagellum, one for which we could sharply limit the set of simpler possiblities so that we could proceed with some kind of convincing proof. Does anyone know of a more simple example? Deans 18:58, 28 February 2007 (EST)
- I agree completely. While you or I might see some system as IC, that is no guarantee that someone else cannot see a pathway as to how it could've evolved. I think this is a very tricky thing to prove, because you would have to show that any and all steps in between are impossible, a very difficult task. As long as we are arguing from Reason, we must show that ideas are necessarily true, not just true as far as we can tell.—unsigned comment by Aquatiki (talk • contribs) --08:49, 24 March 2008 (PDT)
The Darwin quote is missing a vital proposition "If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find out no such case." Intelligent design ideas about irreducible complexity where already around at the time, of course under different names; Darwin wanted to discredit/disprove them, just so you know; in fact he was specifically addressing the issue that would have been brought up by creationists. I would recommend more recent comments/critiques from the scientific community, as many of Darwin's assertions have been in fact WRONG (a lot of time since Darwin has gone by, it is not right to include him in a modern debate) --JFrancis 18:17, 4 June 2010 (UTC)