Canto IV. Dante is so preoccupied with his reflections on the excommunicate that he fails to notice the rapid passage of time. He points out that this is a counter-example to Plato’s claim that different faculties of the mind have different principles or souls; since the powerful exercise of one (Dante’s reflection) inhibits another (his awareness of what is going on around him). St Thomas makes this point in the Summa. The poets climb through a steep and narrow gap onto the next terrace of Ante-Purgatory. Virgil explains to Dante how the passage up the mountain becomes steadily easier. At present it is clearly demanding. Dante is puzzled to see the sun proceeding anti-clockwise through the sky, and Virgil explains why: he is in the southern hemisphere with the sun to the north. The poets meet a group of souls sat still, and, like the excommunicate, with no prayer to repeat. They are the late-repentant, in communion with the Church but having only repented in their last moments, in the case of this group because of their indolence. One of these, known to Dante, explains this to him.

As the slopes of Ante-Purgatory are hard work for Dante, so much of this canto is hard work for those with little interest in astronomy or St Thomas’s philosophy of mind. But the encounter with the indolent late-repentant offers matter for reflection. Salvation is a gift, but it requires our response to ‘work it out in fear and trembling’ in St Paul’s words. This the indolent have failed to do, and so they sit for a period of, what is now enforced, idleness, not even able to pray. The lower slopes of Purgatory bring to mind the carefully balanced affirmations and denials of our faith. We are utterly dependent on God, but by his grace we can truly merit more grace. God’s grace can reach us where-ever we are, but it is our responsibility to take what is offered us through the sacraments and prayer in the ordinary routine of our lives. We can, by grace, build up the disposition of mind to do this. On the other hand, we can build up a contrary disposition to spiritual indolence, which, as is seen on this terrace, it is hard work to slough off.