There is no doubt that we are living in a moment of extraordinary development in the human capacity to decipher the rules and structures of matter, and in the consequent dominion of man over nature.
We all see the great advantages of this progress and we see more and more clearly the threat of destruction of nature by what we do.
There is another less visible danger, but no less disturbing: the method that permits us to know ever more deeply the rational structures of matter makes us ever less capable of perceiving the source of this rationality, creative Reason. The capacity to see the laws of material being makes us incapable of seeing the ethical message contained in being, a message that tradition calls lex naturalis, natural moral law.
This word for many today is almost incomprehensible due to a concept of nature that is no longer metaphysical, but only empirical. The fact that nature, being itself, is no longer a transparent moral message creates a sense of disorientation that renders the choices of daily life precarious and uncertain.
Naturally, the disorientation strikes the younger generations in a particular way, who must in this context find the fundamental choices for their life.
It is precisely in the light of this contestation that all the urgency of the necessity to reflect upon the theme of natural law and to rediscover its truth common to all men appears. The said law, to which the Apostle Paul refers (cf. Rom 2: 14-15), is written on the heart of man and is consequently, even today, accessible.
This law has as its first and general principle, “to do good and to avoid evil”. This is a truth which by its very evidence immediately imposes itself on everyone. From it flows the other more particular principles that regulate ethical justice on the rights and duties of everyone.
So does the principle of respect for human life from its conception to its natural end, because this good of life is not man’s property but the free gift of God. Besides this is the duty to seek the truth as the necessary presupposition of every authentic personal maturation.
– from the Holy Father’s address to the International Congress on Natural Law (2007)