In the Baker Encyclopedia of Christian Apologetics (1999; hereafter: BECA), Geisler has written a fairly long and detailed article on “Faith and Reason”, and the entire article is basically an exposition of the views of Aquinas about faith and the relationship between faith and reason.

There are nine bolded subheadings in Geisler’s article on “Faith and Reason”:

1. Relation of Faith to Reason

2. Three Uses of Reason

3. Divine Authority

4. Reason in Support of Faith

5. Distinguishing Faith and Reason

6. Perfected by Love, Produced by Grace

7. The Limitations of Reason

8. Things Above Reason

9. Summary

1. Relation of Faith to Reason

In part 7 of this series, I started to examine this section of Geisler’s article.  I will now continue that effort.

Here is another interesting passage from that section:

Faith and reason are parallel.  One does not cause the other because “faith involves will (freedom) and reason doesn’t coerce the will” [quoted from On Truth 14.A1.6, by Aquinas]…. A person is free to dissent, even though there may be convincing reasons to believe. (BECA, p.239)

Previously, Geisler stated that “Faith is consent without inquiry in that faith’s assent is not caused by investigation.” (BECA, p.239)

Geisler’s conclusion that “Faith is consent without inquiry” does NOT follow from the premise that “faith’s assent is not caused by investigation.”  Such assent is not caused by investigation because the assent of faith is supposed to be a choice someone makes freely, and faith’s assent is supposed to be made by a free choice because faith is a virtue.  If the assent to a claim was caused or compelled, then the assent would have no merit.

Free will and causation appear to be logically incompatible, at least that is how Aquinas and many Christian thinkers have viewed these two ideas.  But a free choice does NOT imply that the choice is completely uninformed by reasons and evidence.  Reasons and evidence in some cases will point clearly to one particular conclusion and away from other alternative conclusions.  In such cases, reasonable people will be strongly influenced by those reasons and that evidence.  If Aquinas wishes to deny that reason can compel belief, that is one thing, but it would be absurd to deny that reason can have significant influence over a person’s beliefs.  In some cases reason obviously has a very powerful influence over whether a person believes a particular claim or not.

Given these qualifications, the consent of faith may, in some cases be powerfully influenced by reason, even if one wishes to deny that reason can CAUSE a person to assent to a particular claim.  As Geisler says, “A person is free to dissent, even though there may be convincing reasons to believe.”  So, if Aquinas’s Five Ways to prove the existence of God amounted to “convincing reasons to believe” in God, one would still be “free to dissent” and thus if one assented to the claim “God exists” on the basis of those “convincing reasons to believe” that could still count as “faith” and be a belief that was freely chosen (i.e. not CAUSED or compelled by reason).   Therefore, Geisler’s conclusion that “Faith is consent without inquiry” appears to be a misunderstanding of Aquinas’ view of the relationship of faith and reason.

Geisler notes that reason can at least guide us to belief in the existence of God:

However, some Christian truths are attainable by human reason, for example, that God exists and is one.  “Such truths about God have been proved demonstratively by the philosophers, guided by the light of the natural reason” [quoted from Summa Theologica 1a.3.2, by Aquinas] (BECA, p.239) 

So, in the case of the claim “God exists”, Aquinas thinks that reason can deliver the content of that theological claim as well as providing convincing reasons to assent to that claim, though Aquinas would deny that reason can compell belief in the existence of God.

If Aquinas believes that reason is incapable of compelling a person to assent to a belief, even when reason has the strong force of a demonstrative proof, then there appears to be no threat to faith from reason, at least not on this account.  The assent of faith, according to Aquinas must be a matter of free choice, so that faith can be a virtue.  OK, but if reason can never compel belief, then even when reason exerts powerful influence over a person’s choice to believe a particular claim, that belief remains a matter of free choice, and thus it remains a candidate for being the assent of faith.