I don’t suppose that anyone really knows all of the reasons he believes something. Assent is a complicated thing, and we are subject to innumerable influences.

Nevertheless, I have found that, like so many other Catholic converts, I can trace at least some of the steps that led me to the point where I could no longer deny the truth of Catholicism. One of those first steps came while studying Plato’s Republic and what it taught me about Purgatory, even though Plato himself did not believe in Purgatory. Allow me to explain.

In my Protestant days, I thought Purgatory was unbiblical and, therefore, untrue. All of our sins have been forgiven by Christ’s death on the Cross. No more payment was necessary, so there did not need to be any purgation of any kind after the soul’s departure from the body. Made clean by the blood of the Lamb, every person of genuine faith would enter directly into the presence of God the moment after he died.

This picture, of course, is based on a legal view of justice, ethics and atonement: the punishment of sin is exterior and imposed from the outside like a sentence issued from a judge after being convicted of a crime. So, too, the pardon is a legal declaration. All consequence and freedom come from outside of me.

When I encountered Plato, I had already been reading a lot of C.S. Lewis, who writes extensively about virtue and ethical guidelines as “rules for running the human machine.” Lewis’ words were enticing, but for some reason the picture did not form very clearly in my mind because I was still so tied to a legal view of ethics. In a passage where Lewis talks about Purgatory as the heavenly wash room, I couldn’t see how a wash room was really necessary if all sins were forgiven and washed away by Christ when I placed my faith in Him.

Plato’s Republic revolutionized my understanding of virtue and gave me a detailed, though pagan, picture of what human excellence looks like. Previously, I was in the class of people lamented by Allan Bloom: “As it now stands, students have a good image of what a perfect body is and pursue it incessantly. But, deprived of literary guidance, they no longer have any image of a perfect soul, and hence do not long to have one. They do not even imagine that there is such a thing.” Ethics is based on natural law, one of the topics addressed in Pope Emeritus Benedict XVI’s recent letter.

I realized that, yes, there are legal consequences for sin, but we disorder our very selves when we act contrary to our nature. Augustine’s words finally made sense: “Matters are so arranged at [God’s] command that every disordered soul is its own punishment.” Every sin inflicts a wound on our very selves. Our punishment is what we turn ourselves into by our actions. We are forgiven by the Cross, but sanctification is a life-long, and then some (most probably for me at least), process. God is not just pleased with what we do, per se, but who we are. As St. Irenaeus of Lyons said, “The glory of God is a human being fully alive.”

Plato was not the only one to offer this view of the human person. It was the dominant idea throughout the Ancient world and the Middle Ages. It gave new meaning to words “justice” and “justification” encountered so often in Scripture. At this same time, I was realizing that Scripture interpretation was not as clear as I would have liked it to be, so I was open to understanding Scripture within this new-to-me but Ancient framework.

It occurred to me that I will not be perfect, i.e., completely sanctified, at the moment of my death. But I will be perfect in Heaven. There must be, then, some process of change to my very self. This process of being made whole on the inside, not just a change in legal status, could not be an instantaneous change without endangering my identity.

So, while I was still definitely Protestant and very critical of Catholicism, I accepted the fact that Purgatory was possible and even likely. I had discovered a chink in the armor of my Evangelical Protestant worldview. If Purgatory was possible and even likely, what next? It was one step of a long journey, but a pivotal one nonetheless.

As a closing thought, I have to emphasize the role of grace in all of this. First of all, we are wholly reliant on the Divine Help. The Holy Spirit sanctifies us with our cooperation. The desire to become holy is itself a freely bestowed gift. Even theological and philosophical insight is not possible for a human alone. The Spirit opens the heart and mind to truth.