I recently found these two gems in Hans Kung's Infallible: An Inquiry (1970) which I thought were worth passing along to those interested in such things.
For a long time, too, Catholic theologians in their works on apologetics, in the service of the teaching office, were able very successfully to ward off any questioning of infallibility by the use of a basically simple recipe: either it was not an error or--when at last and finally an error could no longer be denied, reinterpreted, rendered innocuous or belittled--it was not an infallible decision (32-33).
Sound like the tactics of anyone we know? Elsewhere Kung says,
And what is meant by "faithfully expounding" the deposit of revelation? "The words `to be faithfully expounded' indicate briefly that there is a historical development of dogma itself, and not merely of theology." On the basis of this second qualification the Roman teaching office seems to be permitted to explicate "authentically" and--as in the case of two new Marian dogmas--even to define infallibly all kinds of things on which not a word was said either in Scripture or in early tradition (74).