Thomas Aquinas connects faith and reason, but does not view them as competing methods of knowledge. That relationship hinges on the foundation of belief in his distinction between “demonstrable beliefs” and “revealed mysteries.”1 The philosophical question is whether the distinction of those grounds also implies their compatibility. Aquinas provides a clear synthesis in the sense that he provides reason a provisional place, places the assent of faith in trust maintained by grace, and allows intellectual obstacles in faithful commitment. That partnership, however, is one that shows how faith and rational inquiry can hold together more effectively than when it is used to establish the authority of revelation for someone who does not already hold it.
Faith can be prepared by reason just as it is prepared by its preconditions, but preparation is not proof of revealed doctrine. There are some preambles, such as God’s existence, that Aquinas is able to demonstrate; there are articles of faith, like the Trinity and the Incarnation, that are beyond demonstration.2 The difference creates a logical connection: A statement of the incarnation of God assumes that God exists, but the existence of God does not imply the existence of God in human form. Thus, even if the preamble were a success, the article would still need to be based on another ground of assent. Furthermore, Aquinas does not demand that all believers make such proofs to be convinced before taking the leap of faith.3 Rational accessibility and actual possession of a proof are thus two different things. This will stop the philosophy expertise from becoming a prerequisite for belief, but will allow probing of claims that reason can handle.
Nevertheless, the preparatory function of reason demands examination, since a philosophical statement can be more convincing than religious language would suggest. In this case, Aquinas’s first-cause argument alone is inadequate to make the morally perfect agent worthy of worship.4 This objection points to the difference between the explanation of causal dependence and the identification of the explanation with the God of religious devotion. A defender might state that one argument cannot prove all divine attributes; another argument can provide what the first argument lacks.5 The answer to this response further narrows Moser’s remarks but also underscores the need for further justification. The first cause is the name given to God’s role as the cause of everything. The connection between the claims of reason and its premises can be defended only as long as the claims assigned to reason are proportionate with what is claimed by the arguments.
Faith provides another basis of assent, but it does not necessarily account to an outsider for that assent. Primarily, Aquinas’s theory of faith is one of intellectual assent to divine command under divine grace and not the assent that takes place through demonstrative evidence.6 Therefore, believing is not just an inference, but the person’s orientation to a trusted divine speaker. The strongest objection is that willing assent cannot make a proposition true. Aquinas’s response to this objection is contained within itself, because he bases his faith on God’s knowledge and truthfulness.7 However, the outsider must have reasons to consider some teachings that they are receiving as a word from God. Lack of demonstration is not sufficient to make something irrational, only the existence of other grounds for trust. The account thus gives an answer to the question of why in the conviction of the theological perspective, faith is more than mere preference that is not supported; it is not simply faith described that makes the theological perspective itself established.
Committed assent is not synonymous with demonstrated understanding, as is shown by the intellectual uncertainty within faith. Gardner distinguishes doubt that denies assent from doubt that can co-exist with assent since the object of the faith is not directly known by the intellect.8 This separation allows the believer not only to stay faithful, but also to have reasons that pull in the direction of another judgment. The philosophical value is that it distinguishes the strength of commitment from the fullness of understanding: commitment does not mean that all objections have been answered.9 However, the distinction also creates a limit. Inquiry for the purpose of understanding an accepted doctrine is not inquiry which is left to the question of truth. That difference cannot be eliminated when movements of doubt are recognized. Faith, then, can engage in serious thought, but faith itself cannot answer the questions which impel serious thought.
These differences, considered together, do more to establish a basis for compatibility than a universal compelling argument for faith. Di Ceglie’s account of grace and Gardner’s analysis of assent provide Thomistic analysis of belief in the context of his theological commitments.10 The philosophical support cannot be detached from the object and should be considered separately, as Moser objects.11 These jobs do not have to mutually exclude each other. They provide answers to other questions: How religious assent is achieved, what an argument proves, and why someone should agree with the conclusion. Confusing those questions would make the partnership appear stronger than its reasoning warrants.
In conclusion, Aquinas’s success was a blended approach of the two, faith and reason. Each of these has a unique function: rational preparation, trust in divine authority and ongoing intellectual inquiry. Their collaboration is not compromised when those tasks are left. The resulting exposition is an illustration of the way in which faith can deal with reason and doubt and yet not sacrifice the necessity of recourse to revelation. Compatibility is therefore important, but is not equivalent to proof.
