Andrew Brown's comment on the debate I had with Michael Reiss missed a critical point.
My contention is that 'the purposeful arrangement of parts' to achieve a specific purpose is the criterion that enables us to recognise design. I argued that the conclusion of design in the bacterial flagellum and in many other biological systems is no different from discerning it for a mousetrap or a Ford Mondeo.
So what makes Intelligent Design fundamentally different from Darwinism? The Darwinian view which dominates biology holds that the design we all see in life is merely illusory and that life is essentially a blind and purposeless phenomenon. Intelligent Design claims that the design is real and demonstrable; we are left to draw our own conclusions about the implications.
How the design is delivered, however, is a separate matter. I was clear that we do not yet know the details of how these designed systems were assembled over the history of life. It was in this context that I made the comment that the operation of natural law might play a part. To imply, as Brown does, however, that intelligent design can be reduced only to the operation of natural law and therefore is essentially indistinguishable from Darwinism is to confuse fundamentally the end (design) with the means of delivering it.
Intelligent Design is an inductive argument from empirical observations like the irreducible complexity of molecular machinery. Intelligent causation as an explanation is consistent with all our experience of finely engineered machines which have intelligent designers. The Darwinian alternative is to propose a phenomenon never observed anywhere, namely that complex machinery can assemble itself without any planning or direction.
Andrew Brown's comment on my debate with Reiss makes a category error. A lack of clarity about the processes by which living systems are assembled does not diminish the perception of their inherent design.