St. Augustine on Truth, Reason, and Divine Illumination

St. Augustine's Defense Against Skepticism

Skepticism, particularly from the New Academy, was defended by denying the possibility of achieving any certainty. "No," says St. Augustine, "even if I were a fool, I would still exist." He argues that the statement "si fallor, sum" (if I err, I am) would always be true, ensuring the certainty of one's existence. However, Augustine asserts that certainty is triple, because man:

• Is (exists)
• Lives
• Understands

The Validity of Knowledge: Inner Experience

Through the certain knowledge that the mind possesses within itself and for itself, in inner experience, St. Augustine establishes the validity of knowledge. Therefore, he contends that one cannot doubt:

• The accuracy of the principles of understanding (e.g., the principle of contradiction).
• The certainty of mathematical truths.
• The accuracy of the external reality in which he lives.

Augustine's Classification of Knowledge

St. Augustine distinguishes various types of knowledge, ensuring its possibility. He primarily categorizes knowledge into two main forms: sensitive knowledge and rational knowledge. Rational knowledge, in turn, may be further divided into lower and higher activities.

Sensitive Knowledge: The Lowest Degree

Sensitive knowledge represents the lowest degree of knowledge. Although it is acquired by the soul, using the senses as instruments, this type of knowledge generates only opinion (doxa). This kind of knowledge is inherently subject to change, as it concerns mutable things. One can observe the clear dependence of Augustinian thought on Platonic ideas here.

Because sensitive knowledge depends on mutable objects and the senses (which are instruments), any deficiency in them can affect the knowledge the soul receives from the sensitive world. The true object of knowledge is not changeable, but the immutable, where truth resides. Sensitive knowledge, by its nature, cannot offer this ultimate truth.

Rational Knowledge: Seeking Universal Truth

Rational knowledge operates on two levels:

Lower Rational Knowledge: Science and Mathematics

In its lower activity, rational knowledge is directed toward understanding what is universal and necessary in temporal reality. This is the kind of knowledge we call science, including mathematical skills. Such knowledge depends on the soul, but it arises in the wake of "contact" with sensible reality. This contact provides the occasion that allows correct ideas to emerge for such universal knowledge.

Higher Rational Knowledge: Divine Illumination

The ultimate ideas, according to Augustine, reside in the mind of God. How, then, does one achieve the knowledge of these divine ideas? Given humanity's separation from purely sensible reality, these ideas can be known only by a special light that God gives the soul for the higher activity of reason. True knowledge, therefore, depends on divine illumination.

Interpreting Divine Illumination

How is this divine illumination interpreted? According to the so-called ontological interpretation of illumination, it would mean that the soul directly contemplates the ideas or essences in the divine mind. However, this interpretation raises significant theological problems, as it implies that the soul somehow contemplates the divine essence itself.