Just considering the encyclicals, it is remarkable the conversation the Holy Father emeritus entertained with the most influential thinkers of our age. His attempt was to engage and to answer the modern intellectual prejudice.
I. Deus Caritas Est
He starts with Nietzsche beginning the first encyclical with his claim that Christianity has harmed eros and made it dirty, while in itself it is clean. This is a prevailing idea today, that the natural state of man is pure and innocent and it is the prudish squint of the Church which spoils it and thereby makes it bad. Cf. par. 3.
The Holy Father answers
1. By showing that eros was drunk with excess and every form of perversion long before Christianity came on the scene.
2. That the ancients themselves were the ones to realize that temperance, purification was necessary for true happiness, fulfillment and peace.
3. That the flesh itself is empty, man is body and soul.
4. Eros inclines and is fulfilled in agape: self-sacrificing love.
II. Spe Salvi
Having referenced Christ the philosopher-shepherd in the first sections of the encyclical, he gives an overview of the modern age hijacking of faith with a newly found faith in...science and praxis as the exclusive instrument of progress beginning with Francis Bacon, then politically implemented with the French Revolution and the positive assessment thereof by Immanuel Kant, Engles and Marx and Theodor W. Adorno.
Cf. par. 16-23.
III. Lumen Fidei (The third encyclical in the trilogy although published by his successor, yet almost unaltered, cf. 7)
Here again Benedict begins with Nietzsche (par. 2), with his formulation of the modern objection to faith as contrary to reason: that humanity is divided between those who follow truth and those who believe. This modern notion is that faith is contrary to intellectual rigor.
The Holy Father answers that true faith (e.g. Catholicism) is first of all concerned with Truth, the ultimate Truth, and that that concern for the ultimate truth is the foundation of all seeking and of all confidence in the solidity of any truth. Without God, without Christ truth has no ground on which to stand! Because God is true the truth is solid!
What is noteworthy is Pope Benedict's boldness in taking on the most iconic of the modern deconstructionist philosophers, the ones who call bad good and good bad, who call what is false true and what is true false. Pope Benedict enters the modern debate and briefly and effectively answers them with the Philosopher Christ! With the wisdom and the power of God their errors are put to shame, by the Vicar of Christ. What centuries of Christian philosophers have not been able to answer (because they have been working within the atheistic presuppositions of our adversaries) he answers using the Word of God and basic common sense and logic. Not just logic though. Logic enlightened and considered in the Light of Faith, as Christians should always act and think, admitting and applying the wisdom that is theirs.
This is why Saint Thomas Aquinas claimed that philosophy after Christ was dead. You cannot be an honest philosopher if you ignore the wisdom of Christ. You will end up in the most ridiculous forms of superstition because you will seek your wisdom in everyone and every philosophy except God. That is prejudicial. Not really honest at all. We cannot dissect wisdom.