Medieval Christian Worldview of St. Thomas Aquinas

Introduction: Sacred Doctrine as the Highest Knowledge

"Man is directed to God, as to an end that surpasses the grasp of his reason… Whereas man's whole salvation, which is in God, depends upon the knowledge of this truth. Therefore, in order that the salvation of men might be brought about more fitly and more surely, it was necessary that they should be taught divine truths by divine revelation." [Pt. I, Q. 1, Art. 1]

For St. Thomas Aquinas, the purpose and meaning of human life in all its aspects are ultimately to be found in God and salvation. "Sacred doctrine" is thus the greatest and most important element of philosophy; for Aquinas, the highest and truest philosophy is Christian philosophy. Sacred doctrine is not just one branch of human science among others, but the most important knowledge available to human beings, for "the purpose of this science, in so far as it is practical, is eternal bliss" [Pt. I, Q. 1, Art. 5].

Sacred doctrine deals, as its object, with something that cannot be directly apprehended or fully known by human knowledge, but only ultimately approached and understood through faith: God Himself. Yet Aquinas is clear that through sacred doctrine humanity can know enough of God and His purposes by understanding the nature of Christian salvation — by "treat[ing] of God viewed as the highest cause — not only so far as He can be known through creatures just as philosophers knew Him… but also so far as He is known to Himself alone and revealed to others" [Pt. I, Q. 1, Art. 6].

The world is the creation of God and is centered, for Aquinas, on God, and all human endeavor should ultimately be directed toward a knowledge of God and the divine mystery of human salvation. It is important to emphasize, however, that Aquinas has a clear position on the human intellectual ability to pursue that knowledge. Aquinas argues that human beings are made human by their intellects, and that they have the ability and duty to use those intellects to apprehend the divine. Human beings are not, therefore, without standing in Aquinas's worldview; as the objects of divine will, they are required to interpret and understand His will through sacred doctrine.

Faith and Reason in Harmony

Sacred doctrine is ultimately based upon faith, and without faith there can be no understanding of the divine. Yet Aquinas argues that faith without intellectual engagement is insufficient:

"This doctrine is especially based upon arguments from authority, inasmuch as its principles are obtained by revelation: thus we ought to believe on the authority of those to whom this revelation has been made… But sacred doctrine makes use even of human reason, not, indeed, to prove faith (for thereby the merit of faith would come to an end), but to make clear other things that are put forward in this doctrine." [Pt. I, Q. 1, Art. 8]

The starting points of this intellectual process are authoritative revelations of divine purpose — first and most importantly through Scripture, and secondly through the interpretations of the Doctors of the Church — mediated through human faith and reason. For Aquinas, faith and reason can work in harmony; there is no necessary tension between them.

The Existence of God and Human Intellect

God is at the heart of Aquinas's worldview and philosophy, and the role of human reason as well as faith comes once more to the fore in the process by which human beings accept the existence of God — for Aquinas is clear that the existence of God is not self-evident. The essence of God is unknown to us, so must be "demonstrated by things that are more known to us… namely, by effects" [Pt. I, Q. 2, Art. 1].

To reach conclusions about the existence of God by studying the world around us will, Aquinas argues, lead inevitably to a knowledge of God, for the world cannot be explained without recourse to God. Thus, once again, human reason is in harmony with revelation and faith in bringing human beings to a fuller knowledge of the Godhead and of salvation.

Conclusion: A Harmonious Vision of the World

Aquinas thus expounds a harmonious vision of the world, in which the truth of divine revelation and the rules of divinely sanctioned conduct are available to guide humanity in its search for salvation and in the mundane affairs of earthly life. The central point for Aquinas is that the human being is an intellectual animal, and it is only through the exercise of that intellect — an intrinsic part of the divinely created human soul — that a full engagement with and understanding of divine purposes can be achieved.