In some commentary on Caritas in Veritate, the point has been made that there are tensions among different statements of Catholic social teaching. Most notably, Populorum Progressio is often mentioned as an outlier in leftward direction.
Fr. Robert A. Gahl, Jr., an associate professor of ethics at the Pontifical University of the Holy Cross, in Rome, made an interesting comment to me the other day. He suggested that one of the purposes of Caritas in Veritate is to apply to Populorum Progressio what has come to be called a hermeneutics of continuity rather than a hermeneutics of rupture, as many on both left and right have done. In other words, the pope is trying to give Populorum Progressio an interpretation that shows it to be consistent with the rest of Catholic social teaching. This would be part of the larger project of John Paul II and Benedict XVI of applying a hermeneutic of continuity to Vatican II teaching. Fr. Gahl noted this passage from the new encyclical:
The link between Populorum Progressio and the Second Vatican Council does not mean that Paul VI’s social magisterium marked a break with that of previous Popes, because the Council constitutes a deeper exploration of this magisterium within the continuity of the Church’s life. In this sense, clarity is not served by certain abstract subdivisions of the Church’s social doctrine, which apply categories to Papal social teaching that are extraneous to it. It is not a case of two typologies of social doctrine, one pre-conciliar and one post-conciliar, differing from one another: on the contrary, there is a single teaching, consistent and at the same time ever new.
Fr. Gahl has some interesting reflections on the content of the encyclical at Mercatornet.