Karl Rahner, S.J, On The Issue Of The "Unchangeable" Teachings

In 1948-9 Karl Rahner, S.J. returned to the theology faculty at Innsbruck and taught on a wide variety of topics which were to become the essays published in Schriften zur Theologie (Theological Investigations). The Investigations is not a systematic presentation of Rahner’s views, but, rather, is a diverse collection of essays on theological topics characterized by his probing, questioning search for truth. 

Rahner was to develop difficulties with Rome. His outspoken, frank approach to issues and his creative, challenging and non-traditional approach to theology often got him into trouble with the authorities who tended to be more traditionally minded, especially on the issue of the "unchangeable" teachings of the Catholic Church. 

In 1962, however, with no prior warning Rahner’s superiors in the Order told him that he was under Roman pre-censorship, which meant that he could not publish or lecture without prior permission. The basic objections of the Roman authorities focused, essentially, on Rahner’s views on the eucharist and Mariology.

Link (here) to the Boston University website