This paper concerns an ethics of our medieval tradition (in particular good, happiness, natural law and virtue) and tries to show how to recover it, facing the problems of pluralism, freedom and scientific approach in modern and contemporary age. The author points out: - The central role of the desire for good and happiness and for goods adequate or inadequate to the openness of desire (particularly of the human person). Today we speak of the meaning of life. - The role of ethical virtues as the flowering of the first principles of natural law. - The principle of the entirety of the good (bonum ex integra causa) in order to judge the moral goodness of an action and as a criterion to compare different ethics ...