I can't help posting this that I just read in De Lubac's "Motherhood of the Church":
Cardinal Suenens recently related a very significant remark that had come straight from the mouth of Father Karl Rahner: 'I asked Father Rahner how he explained the decrease of Marian piety in the Church. His reply is worthy of attention. Too many Christians, he said to me, whatever their religious obedience, have a tendency to make an ideology, an abstraction, out of Christianity. And abstractions have no need of a mother.'
I thought that was beautiful. Two of the best books I have read about Mary were written by the Rahner brothers. Hugo's "Mary and the Church" and Karl's "Mary, Mother of the Lord."