Definition - All parts are required for a given function.  Removal of any one part results in complete loss of that function.

 

Orthodox Darwinian view:
 

"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."

C. Darwin, The Origin of Species,  pg 219.
 

"One hundred and twenty five years on, we know a lot more about animals and plants than Darwin did, and still not a single case is known to me of a complex organ that could not have been formed by numerous successive slight modifications.  I do not believe that such a case will ever be found.  If it is ... I shall cease to believe in Darwinism."

R. Dawkins, The Blind Watchmaker, pg 91.
 

"Evolution is very possibly not, in actual fact, always gradual.  But it must be gradual when it is being used to explain the coming into existence of complicated, apparently designed objects, like eyes.  For if it is not gradual in these cases, it ceases to have any explanatory power at all.  Without gradualness in these cases, we are back to miracle, which is simply a synonym for the total absence of explanation."

R. Dawkins, River out of Eden, pg 83.

 
 

Challenging the sufficiency of Darwinism:
 

"This book is bout an idea - Darwinian evolution - that is being pushed to its limits by discoveries in biochemistry."

Michael Behe, Darwin's Black Box, p 3.
 

The bacterial flagellum and the rotary motor which drives it are not led up to gradually through a series of intermediate structures and, as is so often the case, it is very hard to envisage a hypothetical evolutionary sequence of simpler rotors through which it might have evolved gradually.

Michael Denton, Evolution: A Theory in Crisis, pg 225.
 

There is no hint anywhere of any sort of structure halfway to the complex molecular organization of these fascinating microhairs [cilia] through which their evolution might have occurred.

Michael Denton, Evolution: A Theory in Crisis, pg 108.
 

The irreducible complexity of such bioochemical systems counts powerfully against the Darwinian mechanism and indeed against any naturalistic evolutionary mechanism proposed to date.  Moreover, because irreducible complexity occurs at the biochemical level, there is no more fundamental level of biological analysis to which the irreducible complexity of biochemical systems can be referred and at which a Darwinian analysis in terms of selection and mutation can still hope for a success.

W. Dembski, Intelligent Design, pg 149.
 

"There has never been a meeting, or a book, or a paper on the details of the evolution of complex biochemical systems."

M. Behe, Darwin's Black Box  pg 179.
 

"The impotence of Darwinian theory in accounting for the molecular basis of life is evident not only from the analyses in this book, but also from the complete absence in the professional scientific literature of any detailed models by which complex biochemical systems could have been produced."

M. Behe, Darwin's Black Box, pg 187.
 

It is the sheer universality of perfection, the fact that everywhere we look, to whatever depth we look, we find an elegance and ingenuity of an absolutely transcending quality, which so mitigates against the idea of chance.  Is it really credible that random processes could have constructed a reality, the smallest element of which - a functional protein or gene - is complex beyond our own creative capacities, a reality which is the very antitheses of chance, which excels in every sense anything produced by the intelligence of man?  Alongside the level of ingenuity and complexity exhibited by the molecular machinery of life, even our most advanced artefacts appear clumsy. ....  In practically every field of fundamental biological research ever-increasing levels of design and complexity are being revealed at an ever-accelerating rate.  ....  To those who still dogmatically advocate that all this new reality is the result of pure chance, one can only reply, like Alice, incredulous in the face of the contradictory logic of the Red Queen:

Alice laughed.  "There's no use trying", she said.  "One can't believe impossible things".  "I dare say you haven't had much practice" said the queen.  "When I was your age I did it for half an hour a day.  Why sometimes I've believed as many as six impossible things before breakfast".
 

Michael Denton, Evolution:  A Theory In Crisis, pg 342