The encyclical Aeterni Patris, promulgated by Pope Leo XIII in 1879, represents a milestone in the intellectual history of the Catholic Church. Faced with a modernity marked by philosophical systems leading to skepticism, materialism, and rationalism, the document presents a clear diagnosis and a vigorous solution: the restoration of Christian philosophy, with St. Thomas Aquinas as its master and sure guide. The encyclical argues that modern philosophy, by divorcing reason from faith, has produced "poisonous fruits," generating disorder not only in the field of knowledge but also in social and moral life. In contrast, Thomistic philosophy is presented as a bulwark of truth, an instrument capable of demonstrating the preambles of faith, defending dogmas against errors, and ordering human knowledge in harmony with divine revelation. Leo XIII exhorts bishops, clergy, and academics to "restore the golden wisdom of Thomas and to spread it far and wide," not as a closed system, but as a source of solid and perennial principles capable of illuminating the challenges of any era. The document concludes with an appeal for a united effort so that sound philosophical doctrine may flourish again, serving as a foundation for theology and a sure guide for culture.
🌪️The Diagnosis of a Modern Malady: Practical NaturalismThe encyclical Aeterni Patris identifies the root of modern evils in the separation between faith and reason, a schism that led philosophy to trust presumptuously in its own powers, resulting in contradiction and skepticism (Leo XIII, 1879). This proud autonomy of the intellect is the reflection, in the philosophical field, of what in the spiritual life manifests as "practical naturalism." It is the attempt to organize life without God, or, more subtly, without the need for His interior grace to heal and elevate wounded nature (Garrigou-Lagrange, 1989, v. 1, p. 275). Just as modern philosophy sought a self-sufficiency that led it into error, the soul that lives according to the spirit of nature, relying on its own lights and strengths, ends up judging divine things from an inferior viewpoint, falling into what Scripture calls "spiritual folly" (Garrigou-Lagrange, 1989, v. 1, p. 356). The social and moral disorder denounced in the encyclical is, ultimately, the fruit of disordered souls, whose intellect, unpurified by faith, becomes prey to curiosity, pride, and spiritual blindness.
🏗️The Thomistic Remedy: Beyond Philosophy to Sanctity
In proposing the restoration of Thomism, the intention is not merely academic. The philosophy of St. Thomas Aquinas is presented as a remedy because it offers the intellectual structure that corresponds to the reality of the human being and his ordering to a supernatural end. For the interior life, this translates into the need for "firmness of principles" (Garrigou-Lagrange, 1989, v. 1, p. v). Without a solid metaphysics that recognizes the contingency of the creature and the absolute transcendence of God, the soul can hardly open itself to humility, which is the foundation of the entire spiritual edifice. Thomism, by establishing the real distinction between essence and existence in everything that is not God, provides the rational basis for understanding the mystery of creation ex nihilo and, consequently, for the act of humility that recognizes: "I am He who is; thou art she who is not" (Garrigou-Lagrange, 1989, v. 1, p. 106). Thus, the restoration of sound philosophy is not an end in itself, but an indispensable means to purify the intellect, ordering it to the truth and preparing it to receive the superior light of faith.
✨The Harmony of Faith and Reason: The Purification of the Intellect
Aeterni Patris insists that faith does not destroy reason but perfects it, elevating it and protecting it from error (Leo XIII, 1879). In the spiritual life, this principle is actualized in the active purification of the intellect. The human intellect, wounded by original sin, tends toward vain curiosity, presumption, and spiritual blindness. The virtue of faith, therefore, acts not only as a set of truths to be believed but as a principle of purification (Garrigou-Lagrange, 1989, v. 1, p. 359). The "spirit of faith" consists in judging all things—ourselves, our neighbor, events—under the light of revelation. This continuous exercise of submitting one's own judgment to the authority of God revealing is the true mortification of the intellect. It is what allows the soul to pass from a horizontal view of things, immersed in time, to a vertical view that connects them to the immovable instant of eternity (Garrigou-Lagrange, 1989, v. 1, p. 346). Reason, thus purified and elevated by faith, becomes docile to the inspirations of the gifts of the Holy Spirit, especially understanding and wisdom, which lead it to a living and savory penetration of the divine mysteries, which is infused contemplation (Garrigou-Lagrange, 1989, v. 2, p. 313).
🌳The Fruits of True Philosophy: Order in the Soul and in Society
The encyclical emphasizes that the restoration of Thomistic philosophy would bring great benefits to society, promoting order, justice, and peace (Leo XIII, 1879). This external peace, however, is a reflection of the "tranquility of order" that must first reign in the soul. Disordered self-love is the cause of all disunity, as it leads man to seek material goods that divide, rather than spiritual goods that unite (Garrigou-Lagrange, 1989, v. 1, p. 141). A philosophy that does not order man to God, his Ultimate End, will inevitably leave him captive to his egoism. Conversely, a realistic and theocentric philosophy, like Thomism, by showing the hierarchy of goods, educates the will so that it conforms to the divine will. The ultimate fruit of sound philosophy, therefore, is not only a more just society but souls that, having their intellects and wills purified, walk on the way of perfection, whose goal is intimate union with God, the prelude to eternal life.
📚References
GARRIGOU-LAGRANGE, R. The Three Ages of the Interior Life. 2 vols. Rockford: TAN Books, 1989.
LEO XIII. Aeterni Patris. Rome, 1879.