"The Word 'Design' Almost Unavoidably Comes to Mind"

Christian de Duve is one of the many voices who acknowledge the evidence of design in nature.  Vital Dust: Life as a Cosmic Imperative, pp 9-10:

Cells are so obviously programmed to develop according to certain lines, organs adapted to perform certain functions, organisms suited to certain environments, that the word design almost unavoidably comes to mind. 

But then he joins the many who say that, despite this evidence, other explanations "must" be found:

Life is increasingly explained strictly in terms of the laws of physics and chemistry. Its origin must be accounted for in similar terms. 

So past explanation "trends" have to limit future explanations?  This is absurd.  It looks like his worldview is driving this, not the evidence.

Similar comments on the evidence for design are here.