“Over the years I have become more and more convinced that the ideologies of evil are profoundly rooted in the history of European philosophical thought. Here I should mention some aspects of European history, and especially its dominant cultural trends. When my encyclical on the Holy Spirit was published, there were some sharply negative reactions from certain quarters in the West. What prompted these reactions? They arose from the same sources as the so-called European Enlightenment over two centuries earlier particularly the French Enlightenment, though that is not to exclude the English, German, Spanish, and Italian versions. The Enlightenment in Poland followed a path all its own.

Russia, on the other hand, apparently escaped the upheaval of the Enlightenment. There, the crisis of Christian tradition arrived from a different direction, erupting at the beginning of the twentieth century with even greater violence in the form of the radically atheist Marxist revolution.

In order to illustrate this phenomenon better, we have to go back to the period before the Enlightenment, especially to the [French] revolution brought about by the philosophical thought of Descartes.

The cogito, ergo sum (I think, therefore I am) radically changed the way of doing philosophy. In the pre-Cartesian period, philosophy, that is to say the cogito, or rather the cognosco, was subordinate to esse (i.e., being, existence,  Exodus 3:14; Jn 8:58) , which was considered prior.

To Descartes, however, the esse
seemed secondary, and he judged the cogito (thinking) to be prior.

This not only changed the direction of philosophizing, but it marked the
decisive abandonment of what philosophy had been hitherto, particularly the philosophy of Saint Thomas Aquinas, and namely the philosophy of esse.

Previously, everything was interpreted from the perspective of esse and an explanation for everything was sought from the same standpoint. God as fully Self-sufficient Being (Ens subsistens) was believed to be the necessary ground of of all created beings, including man. The Cartesian ‘cogito, ergo sum’ marked a departure from that line of thinking….

After Descartes philosophy became a science of pure thought both within the created world and the Creator Himself. All esse remained within the ambit of this cogito as the content of human consciousness, Philosophy concerned itself with beings as content of consciousness and not existing independently of it.

According to the logic of cogito, ergo sum, God was *reduced to an element within human consciousness”; no longer could he be considered the ultimate explanation of the human sum. Nor could he remain as, the “Self-sufficient Being,” as the Creator, the One who gives existence, and least of all as the one who gives himself in the mystery of the Incarnation, the Redemption, and grace.

The God of Revelation had ceased to exist for Cartesian  thinkers as “God of the philosophers.” All that remained was *the idea of” God, a topic for free exploration by human thought.

Evil. Man remained alone.

In this way, the foundations of the “philosophy of evil” also collapsed. Evil, in our realist sense, can only exist in relation to good and, in particular, in relation to God, the supreme Good. This is the evil of which the Book of Genesis speaks. It is from this perspective that original sin can be understood, and likewise all personal sin. This evil was redeemed by Christ on the Cross.

To be more precise, man was redeemed and came to share in the life of God through Christ’s saving work. All this, the entire drama of salvation history, had disappeared as far as the Enlightenment was concerned. Man remained alone: alone as creator of his own history and his own civilization alone as one who decides what is good and what is bad, as one who would exist and Deus non daretur, even if there were no God.

If man can decide by himself, without God, what is good and what is bad, he can also determine that a group of people is to be annihilated. Decisions of this kind were taken, for example, by those who came to power in the Third Reich by democratic means, only to misuse their power in order to implement the wicked programs of National Socialist ideology based on racist principles.

Similar decisions were also taken by the Communist party in the Soviet Union and in other countries subject to Marxist ideology. This was the context for the extermination of the Jews, and also of other groups, like the Romany peoples, Ukrainian peasants, and Orthodox and Catholic clergy in Russia, in Belarus, and beyond the Urals. Likewise all those who were “inconvenient” for the regime
were persecuted.

— from Memory and Identity by Pope John Paul II, by Rizzoli International Publications, NY, NY 2005.