It goes without saying that this book is in no way an exercise of the magisterium, but is solely an expression of my personal search "for the face of the Lord" (cf. Ps 27:8). Everyone is free, then, to contradict me. I would only ask my readers for that initial goodwill without which there can be no understanding.It is reasonable to assume that the same applies to an interview given to a journalist.
Vatican II's Dogmatic Constitution Lumen Gentium (n.25)speaks of a religious submission of mind and will which should be shown to the bishops teaching on matters of faith and morals in communion with the Roman Pontiff and says:
This religious submission of mind and will must be shown in a special way to the authentic magisterium of the Roman Pontiff, even when he is not speaking ex cathedra.This religious submission of mind and will is not required when the Pope is engaging in a "personal search" or answering questions in an interview - since this is not an exercise of the magisterium.
Nevertheless, Catholic theology has the concept of a "probable opinion" and the Pope is a theologian in his own right. Therefore his opinion on a moral matter must be regarded as a probable one which it is legitimate for a person to follow. Other theologians may disagree and present a different opinion which may also be a probable opinion.