The Rite: The Making of a Modern Exorcist by Matt Baglio

office, not of their nature. If you seek the name of their nature, it is ‘spirit’; if you seek the name of their office, it is ‘angel’: from what they are, ‘spirit,’ from what they do, ‘angel.’“
    There has been much speculation over the years about what might constitute the nature of a pure spirit. And while his writings on the subject are not a part of official Church doctrine, a majority of Catholic theologians follow the teachings of Thomas Aquinas, also known as the Angelic Doctor. Aquinas explains that pure spirits are not composed of matter and form, but of essence and existence, act and potentiality. Where the early Church Fathers fell short, Aquinas suggests, was in not according enough importance to intelligence. Because of their wholly spiritual nature, angels are complete beings and occupy “the first and highest place in the scale of created things,” nearer to the likeness of God, who is pure spirit, rather than man, who is a mix of the spiritual (soul) and material (body).
    Every angel is a distinct being endowed with intellect and free will. However, as Aquinas explains, this doesn't mean that the angels are composed only of intellect, but rather that their knowledge is derived from the intellect, compared to a human soul that attains knowledge through both the intellect and senses. As theologian A. M. Lepicier notes, “An angel possesses such penetration that he is able, at one glance, to take in the whole field of science laying open to his perception, just as we, at a glance, can take in the entire field of vision lying exposed to our eyes.”
    For the ministry of an exorcist, perhaps the most important distinction that Aquinas makes is that since angels (or demons) do not occupy space, therefore they cannot be physically present in a place like a person can. In this way, they are not anywhere. Instead, when a demon is alleged to move an object (slam a door, for instance, or slide a chair across a room), the demon is acting on that object.
    Their being immaterial means that angels do not move from point A to B by any kind of locomotion, but instead suddenly shift their activity from one point or place to a different one. Some theologians have likened this movement to the human mind, which can instantly transfer thoughts over long distances or onto random objects.
    Since the Church teaches that God never rejects his creatures, even when they use his gifts for evil means, the Devil still retains his former angelic stature and powers. As Saint Augustine established, though, God does not give Satan a free hand, otherwise “no man would be left alive.” Theologians stipulate that the Devil and the fallen angels are limited in their actions in two main ways: by the limits of their nature as created beings, and by the will of God.
    LIMITS OF THE DEVIL BASED ON HIS NATURE
    The Catholic Church teaches that no matter how superior he is to humans, the Devil is still a finite creature. He cannot, for example, perform true miracles, because by definition a miracle is something that surpasses the power of all created nature. To perform a miracle requires “supernatural” power, and Satan has only “preternatural” power. He can, however, create the appearance of a miracle since his powers allow him to surpass the limits of human abilities.
    The Devil is also limited in his ability to know the secrets of the inner heart, a field strictly open to God, who is all-knowing, say theologians. However, according to exorcists, the Devil can tell what we are thinking by using his superior powers of observation, just as a physician might glean some information about a man's health by checking his pulse.
    The Devil cannot foresee the future, say exorcists. He can, however, fake the appearance of psychic ability by accurately “predicting” what will happen based on his knowledge of human nature and the powers he has as a spirit.
    LIMITS OF THE DEVIL BASED ON GOD'S WILL
    The second limitation on the Devil's