SUMMARY: Gaudium et Spes constitutes a fundamental starting point for a dialogue with the contemporary world; in particular, it becomes evident that the developments of science and technology must be interpreted according to the category of the « signs of the times », namely through a perceptive activity, which is the precise role of moral theology; even though this needs the contribution and the specific competences of experts in the various disciplines of contemporary knowledge. As to the complex themes of computer science and of artificial intelligence, with the consequent implications of ethical, social, cultural, juridical character, the potentialities and the limitations envisaged in the culture of programming are put in the limelight; the radical differences between human rationality and machine rationality are also made evident. The article shows clearly the inadequacy of utilitaristic ethics, such as that which is associated with the theory of rational choices and social control, on the basis of computer science. Ethics must make reference to the nature of man, to his characteristics of being open to the dimension of transcendency and able to establish infinite relationships with other creatures and with Being. The christian role in the presence of the insufficiency of the various rationalistic and utilitaristic schematization of existence is to bear witness to the values of gratuity and to operate in all fields so that the new technological instruments become true instruments of human progress.