Now let us go directly to the question of evolution and its mechanisms. Microbiology and biochemistry have brought revolutionary insights here. They are constantly penetrating deeper into the inmost mysteries of life, attempting to decode its secret language and to understand what life really is. In so doing they brought us to the awareness that an organism and a machine have many points in common. For both of them realize a project, a thought-out and considered plan, which is itself coherent and logical. Their functioning presupposes a precisely thought-through and therefore reasonable design. But in addition to this commonality there are also differences. A first and somewhat unimportant one may be described as follows: An organism is incomparably smarter and more daring than the most sophisticated machines. They are dully planned and constructed in comparison with an organism. A second difference goes deeper: An organism moves itself from within, unlike a machine, which must be operated by someone from without. And finally there is a third difference: An organism has the power to reproduce itself; it can renew and continue the project that it itself is. In other words, it has the ability to propagate itself and to bring into existence another living and coherent being like itself.
At this point something unexpected and important appears, which Monod calls the platonic side of the world. This means that there is not only becoming, whereby everything is in constant change, but also permanency — the eternal ideas that shine through reality and that are its enduring and formative principles. This permanency is so constituted that every organism reproduces its pattern — the project that it is. Every organism is, as Monod asserts, conservatively designed. In propagating itself it reproduces itself exactly. Accordingly Monod offers this formula: For modern biology evolution is not the specific property of living beings; their specific property is, rather, precisely that they are unchanging: they reproduce themselves; their project endures.
Monod nonetheless finds the possibility for evolution in the fact that in the very propagation of the project there can be mistakes in the act of transmission. Because nature is conservative, these mistakes, once having come into existence, are carried on. Such mistakes can add up, and from the adding up of mistakes something new can arise. Now an astonishing conclusion follows: It was in this way that the whole world of living creatures, and human beings themselves, came into existence. We are the product of “haphazard mistakes.”
What response shall we make to this view? It is the affair of the natural sciences to explain how the tree of life in particular continues to grow and how new branches shoot out from it. This is not a matter for faith. But we must have the audacity to say that the great projects of the living creation are not the products of chance and error. Nor are they the products of a selective process to which divine predicates can be attributed in illogical, unscientific, and even mythic fashion. The great projects of the living creation point to a creating Reason and show us a creating Intelligence, and they do so more luminously and radiantly today than ever before. Thus we can say today with a new certitude and joyousness that the human being is indeed a divine project, which only the creating Intelligence was strong and great and audacious enough to conceive of. Human beings are not a mistake but something willed; they are the fruit of love. They can disclose in themselves, in the bold project that they are, the language of the creating Intelligence that speaks to them and that moves them to say: Yes, Father, you have willed me.
Source: “In the Beginning….” A Catholic Understanding of the Story of Creation and the Fall excerpts from Cardinal Joseph Ratzinger (Pope Benedict XVI)