The irony of God's non-interference
If God isn't imposing his strict will on reality at every second, then what is he or she doing? Erasmus is interested in exploring his religious opinion about God's non-interference, because Erasmus's own experience of life and reality leads him to conclude that God is in fact not interfering in our fate nearly as much as we might believe. What we often think of as divine interaction is simply the natural effects of our human will, says Erasmus.
The irony of the church
Erasmus believes that the Catholic church is an inherently ironic institution, because he feels that the church exists in such a way that it could not be the true Christian religion, although it is literally the standard of his day. He explains that the Bible discusses false versions of the religion dominating during certain periods of history. He is not a fan of the church.
The irony of fate
Although it certainly feels that fate is guiding human experiences, Erasmus argues that fate doesn't really work the way Luther says it does. It isn't like God is deciding what will become of us, says Erasmus. Rather, he builds a network of systems, so that our human decisions are met with divine consequences. In other words, Erasmus is think of justice as a karmic system, in a way, because he views our "fate" as the manifestation of our decisions.
The irony of evil
Technically speaking, evil is ironic in the Christian faith, because if God is almighty and all-knowing, then why would he allow evil to exist? This classic problem of Christian theology is called the problem of evil, and to explain that problem is called a "theodicy." In Erasmus's theodicy, God intimately understands the systems that govern our reality, and he understands his creatures, but Erasmus believes God lets us choose. That means that in Erasmus's opinion, evil is a necessary byproduct of the gift of free will.
The irony of reality
Reality itself is ironic for Erasmus, because he views judgment and fate as natural parts of sorting through human free will. In his imagination, it's a little like we're learning the over-arching rules of the game (in Christianity, the primary rule would be to love all human beings and do no unnecessary harm), but within those rules, we can manifest whatever fate we are willing to embody, in Erasmus's opinion.
