“When the sense of God is lost, there is also a tendency to lose the sense of man, of his dignity and his life; in turn, the systematic violation of the moral law, especially in the serious matter of respect for human life and its dignity, produces a kind of progressive darkening of the capacity to discern God’s living and saving presence.”— Evangelium vitae 21

http://www.vatican.va/holy_father/john_paul_ii/encyclicals/documents/hf_jp-ii_enc_25031995_evangelium-vitae_en.html