Augustine on Reason and Faith: Illumination, Memory, and Will

Posted on Feb 14, 2026 in Philosophy and ethics

Reason and Faith

Reason and faith. Augustine lived with great intensity the problem of the relationship between reason and faith. In his youth, convinced by the alleged incompatibility between the two, he left the Church; when he returned to its bosom he insisted that the intellectual, in order to believe, must not abdicate his rational demands.

  1. There is only one truth about things, illuminated by two sources of light: reason and faith. Faith is the more powerful of the two, enabling the fullness of truth.
  2. Reason and faith are harmonious yet distinct and not confused. Augustine is very clear about what each is and what the other is (a distinction that, moreover, is available to anyone).
  3. Reason and faith work together harmoniously in the discovery of the one truth. Augustine’s formula is often rendered in Latin as “Crede ut intelligas; intellige ut credas.” (“Believe so that you may understand; understand so that you may believe”).

First or Imprinted Illumination

First or imprinted illumination: Metaphysical illumination therefore involves two stages. The first is the imprinted (or natural, necessary) illumination, both in bodies and in spirits.

a) In bodies: there is an impression of what is called physical numbers, space, and time. Numbers are principles of order and proportional regulation. Number implies necessity and determinism, and means that material things act according to necessary laws (i.e., they have a “number,” a way of being that always makes them behave in a fixed and determined way).

b) In spiritual beings: there is an impression of spiritual numbers, which are of two kinds: logical numbers and ethical issues.

  1. The numbers are the foreknowledge: logic, memory, notions, and first principles of scientia (for example, the notion of unity or the principle of contradiction). Thanks to the logical numbers, the memory may come to recognize the numbers printed on things (= the way of being), and achieve awareness about them.
  2. The ethical issues are themselves of two kinds: the rules of wisdom and the light of virtues.

Second or Formed Illumination

Second or formed illumination: This second illumination derives from the first and consists of the forms taken by each person to express and act. It is given differently in bodies and minds:

a) In material bodies it is necessary. The physical numbers imprinted impose necessity and determinism: material beings act according to necessary laws.

b) In spiritual beings (such as the human soul) the ethical issues are not necessary. They regulate moral action but do not determine it. Therefore, they express an illumination or formation that is free and personal: it may be given or not, depending on the positive or negative choice of the person.

  1. Positive option. A positive choice Augustine called conversion (“turning inward”), because the person turns toward his own nature, that is, “becomes himself.” When he attains the second enlightenment or formation, the person becomes a formed and perfect creature.
  2. Negative option. On the negative option, however, the flame is of separation (“removal”), because the person leaves his own nature, “is not himself.” By this means the person is deprived of the second formation, and becomes a deformed child. This is the case of the man who loves himself above

Intellectual Knowledge

Intellectual knowledge: According to Augustine, what happens is this:

  1. Things have been made and formed by God, who has made them a reflection of his own perfection. God acts wisely according to a plan or model, and that model consists of the ideas that are in his own Mind. Things therefore imitate, however imperfectly, the ideas of the divine Mind and resemble them.
  2. Moreover, that same God pours into the depths of our memory the ideas of all things.
  3. In front of us are real things; for example, a tree. What we perceive with the senses—sight, touch, smell—is significant. As what we perceive through the senses corresponds to notions that are in the depths of our memory (both of which are copies of the ideas in God), the sensory perception of that tree awakens in us the corresponding notion (that of ‘tree’), so we can understand what that thing is (that is, we understand that “this is a tree”). Thus, implicit knowledge becomes explicit, and a notion deep in hidden memory becomes a concept reflected in the intelligence.