Essential Incompleteness of All Science

What makes the origin of life and of the genetic code a disturbing riddle is this: the genetic code is without any biological function unless it is translated; that is, unless it leads to the synthesis of the proteins whose structure is laid down by the code. But … the machinery by which the cell (at least the non-primitive cell, which is the only one we know) translates the code consists of at least fifty macromolecular components which are themselves coded in the DNA. Thus the code can not be translated except by using certain products of its translation. This constitutes a baffling circle; a really vicious circle, it seems, for any attempt to form a model or theory of the genesis of the genetic code. Thus we may be faced with the possibility that the origin of life (like the origin of physics) becomes an impenetrable barrier to science, and a residue to all attempts to reduce biology to chemistry and physics.
Karl Popper, one of the most respected philosophers of science in modern times - Popper, K.R., 1974. Scientific Reduction and the Essential Incompleteness of All Science. In Ayala, F. and Dobzhansky, T., eds., Studies in the Philosophy of Biology, University of California Press, Berkeley, p. 270