I did misread that post, but it seems that JPII didn't have that different of a position on evolution. While he did state that this theory was worthy of exploration, he did not contradict Pius XII's stand and relied on his conclusions, that the Bible is the gospel truth.
excerpts:
http://www.cin.org/jp2evolu.htmlMagisterium Is Concerned with Question of Evolution
For It Involves Conception of Man
Pope John Paul II
Message to Pontifical Academy of Sciences
October 22, 1996
I am pleased with the first theme you have chosen, that of the origins of life and evolution, an essential subject which deeply interests the Church, since Revelation, for its part, contains teaching concerning the nature and origins of man. How do the conclusions reached by the various scientific disciplines coincide with those contained in the message of Revelation? And if, at first sight, there are apparent contradictions, in what direction do we look for their solution? We know, in fact, that truth cannot contradict truth (cf. Leo XIII, Encyclical Providentissimus Deus). Moreover, to shed greater light on historical truth, your research on the Church's relations with science between the 16th and 18th centuries is of great importance.
In his Encyclical Humani generis (1950), my predecessor Pius XII had already stated that there was no opposition between evolution and the doctrine of the faith about man and his vocation, on condition that one did not lose sight of several indisputable points (cf. AAS 42 <1950>, pp. 575-576). For my part, when I received those taking part in your Academy's plenary assembly on 31 October 1992, I had the opportunity, with regard to Galileo, to draw attention to the need of a rigorous hermeneutic for the correct interpretation of the inspired word. It is necessary to determine the proper sense of Scripture, while avoiding any unwarranted interpretations that make it say what it does not intend to say. In order to delineate the field of their own study, the exegete and the theologian must keep informed about the results achieved by the natural sciences (cf. AAS 85 <1993> pp. 764-772; Address to the Pontifical Biblical Commission, 23 April 1993, announcing the document on The interpretation of the Bible in the Church: AAS 86 <1994> pp. 232-243).
Evolution and the Church's Magisterium
Pius XII added two methodological conditions: that this opinion should not be adopted as though it were a certain, proven doctrine and as though one could totally prescind from Revelation with regard to the questions it raises. He also spelled out the condition on which this opinion would be compatible with the Christian faith, a point to which I will return. And, to tell the truth, rather than the theory of evolution, we should speak of several theories of evolution. On the one hand, this plurality has to do with the different explanations advanced for the mechanism of evolution, and on the other, with the various philosophies on which it is based. Hence the existence of materialist, reduc tionist and spiritualist interpretations. What is to be decided here is the true role of philosophy and, beyond it, of theology.
5. The Church's Magisterium is directly concerned with the question of evolution, for it involves the conception of man: Revelation teaches us that he was created in the image and likeness of God (cf. Gn 1:27-29). The conciliar Constitution Gaudium et spes has magnificently explained this doctrine, which is pivotal to Christian thought. It recalled that man is :the only creature on earth that God has wanted for its own sake" (n. 24). In other terms, the human individual cannot be subordinated as a pure means or a pure instrument, either to the species or to society, he has value per se. He is a person. With his intellect and his will, he is capable of forming a relationship of communion, solidarity and self-giving with his peers. St Thomas observes that man's likeness to God resides especially in his speculative intellect for his relationship with the object of his knowledge resembles God's relationship with what he has created (Summa Theologica, I-II, q. 3, a. 5, ad 1). But even more, man is called to enter into a relationship of knowledge and love with God himself, a relationship which will find its complete fulfilment beyond time, in eternity. All the depth and grandeur of this vocation are revealed to us in the mystery of the risen Christ (cf. Gaudium et spes, n. 22). It is by virtue of his spiritual soul that the whole person possesses such a dignity even in his body.
Pius XII stressed this essential point: if the human body takes its origin from pre-existent living matter the spiritual soul is immediately created by God ("animal enim a Deo immediate creari catholica fides nos retinere inhet"; Encyclical Humani generic, AAS 42 <1950>, p. 575).
7.
In conclusion, I would like to call to mind a Gospel truth which can shed a higher light on the horizon of your research into the origins and unfolding of living matter. The Bible in fact bears an extraordinary message of life. It gives us a wise vision of life inasmuch as it describes the loftiest forms of existence. This vision guided me in the Encyclical which I dedicated to respect for human life, and which I called precisely Evangelium vitae.