Does Thomism Lead to Catholicism? (2014)
by Norman L. Geisler
Thomas Aquinas, the great philosopher and theologian, was a Roman Catholic. And there are a growing number of non-Catholic scholars who have become Thomists. And some of these have become Roman Catholics. Is there a logical connection? Does Thomism naturally lead to Catholicism? It is natural that one would want to examine this connection.
The Reason Some Non-Catholic Thomists become Roman Catholic
There are a variety of reasons why non-Catholics become Roman Catholic. Let us examine some of them. There is the appeal of antiquity, unity, continuity, beauty, fraternity (or paternity), intellectuality, and a desire for certainty.[1] Any one or more of these appeals to some evangelicals. It is noteworthy that none of these or combination of them is a valid test for truth.
Few evangelicals become Catholic because they became convinced by the study of Scripture that Rome is the true Church. Hardly anyone reasons his way to Rome purely by an objective study of the evidence. For example, one recent convert to Catholicism wrote, “My family is Catholic. They wanted me to return, and the Bible says we should honor our parents!” Clearly none of these reasons are good tests for the truth of a religion. By the same logic, one could argue for becoming a Hindu, Buddhist, or even an atheist, if their family belonged to that group. Or, one could become Eastern Orthodox, if he was looking for a tradition older than his.
We have weighed the many reasons some evangelicals have become Catholic,[2] and almost no one said it was because their study of Thomistic philosophy led them there. As for the appeal of the intellectual tradition in Catholicism, I have a Ph.D. in philosophy from a Catholic (Jesuit) institution and have never once been tempted to become a Roman Catholic. I have used my scholarly training in both traditions to compare them.[3] My co-author Ralph MacKenzie and I both have Catholicism in our background. We have studied both sides carefully, and we see no reason to swim the Tiber.
One recent convert to Catholicism admits that it was not good reasoning that led him to Rome but faith. He said, “The false disciples only follow Jesus when they agree with his teaching. If I am very honest, the rationalism of my evangelical faith would have put me in the first camp (those who reject it because it is hard to understand) for I rejected the doctrine of the Real Presence based on theological arguments (It is a hard teaching), rather than placing my faith in Christ who taught it” (emphasis added). Of course, once one places his faith in the Roman system (for whatever reason), the rest is all part of a packaged deal.
Whatever the reason is that people become Catholic, I have never seen anyone make the case that Roman Catholicism flows logically from Thomistic philosophy. The reason for this is simple: there is no logical connection between them. Aquinas himself said there is no logical connection between Thomism and Roman Catholicism.[4] Further, experience shows that there are many Thomists who are not Roman Catholic.
The Thomistic Distinction Between Faith and Reason
Aquinas believed that faith and reason were such distinct domains that even belief in God could not be an object of both faith and reason simultaneously.
The Formal Distinction Between Faith and Reason
Although Aquinas did not actually separate faith and reason, he did distinguish them formally. He affirmed that we cannot both know and believe the same thing at the same time. For “whatever things we know with scientific [philosophical] knowledge properly so called we know by reducing them to first principles which are naturally present to the understanding. All scientific knowledge terminates in the sight of a thing which is present [whereas faith is always in something absent]. Hence, it is impossible to have faith and scientific [philosophical] knowledge about the same thing.”[5]
The Object of Faith is Beyond Reason
For Aquinas, the object of faith is above the senses and understanding. “Consequently, the object of faith is that which is absent from our understanding.” As Augustine said, we believe that which is absent, but we see that which is present.[6] So we cannot prove and believe the same thing. For if we see it, we do not believe it. And if we believe it, then we do not see it. For “all science [philosophical knowledge] is derived from self-evident and therefore seen principles …. Now, … it is impossible that one and the same thing should be believed and seen by the same person.”[7] This means “that a thing which is an object of vision or science for one, is believed by another.”[8] It does not mean that one and the same person can have both faith and proof of one and the same object. If one sees it rationally, then he does not believe it on the testimony of others. And if he believes it on the testimony of another, then he does not see (know) it for himself.
We Can Reason about Faith but not to Faith
Nonetheless, “this does not prevent the understanding of one who believes from having some discursive thought of comparison about those things which he believes.” Discursive thought, or reasoning from premises to conclusions, is not the cause of the assent of faith. Nonetheless, such reasoning “can accompany the assent of faith.” The reason they are parallel but one does not cause the other is that “faith involves will (freedom) and reason doesn’t coerce the will.”[9] That is, a person is free to dissent even though there may be convincing reasons to believe.
Reason Cannot Produce Faith
Reason accompanies but does not cause faith. “Faith is called a consent without inquiry in so far as the consent of faith, or assent, is not caused by an investigation of the understanding.”[10] Commenting on Ephesians 2:8-9, Aquinas contends that “free will is inadequate for the act of faith since the contents of faith are above reason … so, reason cannot lead someone to faith.”[11] At best, reason is the preamble to faith in God and in Christ. So, the Christian Faith as such does not follow logically from philosophy—even Thomistic philosophy. The best philosophy can do is to prepare the way for faith, but it does not logically lead to faith, let alone to a particular faith like the Roman Catholic Faith.
Faith Goes Beyond Reason
A philosophical argument contains no premises borrowed from faith. It stands on its own two philosophical “feet.” Further, according to Aquinas, unique doctrines of the Christian Faith (such as the Trinity and the Incarnation of Christ) are not the result of human reason. No rational process, no matter how sophisticated, can attain to these unique Christian doctrines. They are not contrary to reason (since there is no contradiction in them), but they go beyond reason. Given this difference between what can be known by reason and what can be known only by faith, it is obvious that Thomistic philosophy does not lead logically to Roman Catholicism.
Thomists Who Were Not Roman Catholic
Not only is there no logical connection between Thomism and Catholicism, but historically there is no actual connection, for many Thomistic philosophers have not been Roman Catholic. Eric Mascal was an Anglican Thomist. David Johnson is a Lutheran Thomist. John Gerstner, R. C. Sproul, and Arvin Vos were Reformed evangelical Thomists. Win Corduan and I are non-denominational, evangelical Thomists. Thomas Howe and Richard G. Howe are Baptistic Thomists. Joseph Holden is a Calvary Chapel Thomist. Mortimer Adler saw no contradiction in being a Jewish Thomist for many years (before he became a Catholic), and so on. There are many more.
It is true that a number of evangelical Thomists have become Roman Catholic (e.g., Thomas Howard, J. Budziszewski, and Francis J. Beckwith). However, none of them did so because the philosophical principles of Thomism drove them there. The truth is that there is no logical connection between them. Thomistic philosophy as such does not logically or philosophically lead to Roman Catholicism, any more than it leads to being a Presbyterian or a Baptist. So, if a Thomist becomes a Roman Catholic, it is not because of any philosophical necessity arising out of Thomism. Thomism is a matter of reason and Roman Catholicism is a matter of faith.
This is not to say that some evangelicals who do not have a very deep liturgical, aesthetic, or intellectual history are not attracted to Catholicism. Some are, but some are also attracted to Eastern Orthodoxy or Anglicanism. And many remain content with their evangelical faith—for good reasons. Converted Catholic Chris Castaldo expressed this in his book Holy Ground when he rejoiced in the sense of liberation from ritual and guilt he never had in Romanism.[12] Tens of thousands of former Catholics who have become evangelical were attracted by the personal, Bible-based experiences evangelicalism provided with the simple Gospel message and a personal relation with Christ they obtained through it.
I have a strong background in Catholicism, having been trained in two Jesuit institutions, with a PhD in philosophy from Loyola University. However, there are several basic reasons that I have not been attracted to Catholicism. First, I am satisfied with being an evangelical doctrinally, experientially, and philosophically. Second, I have not seen any convincing reasons biblically or otherwise to tempt me to become Roman Catholic. Third, my systematic study of Catholicism has convinced me that it is based on unbiblical and unreasonable grounds. Fourth, I have never had the tendency to confuse lace and grace, or to connect ritual and reality very closely. Finally, there are some Catholic doctrines and practices that I find unbiblical and even distasteful such as, purgatory, praying for the dead, indulgences, venerating images, praying to Mary, venerating Mary, the bodily assumption of Mary, worshipping the consecrated host, and the infallibility of the Pope—to mention a few.
The Protestant Dimensions in Thomas Aquinas
Even though there is no logical connection between Thomistic philosophy and Catholicism, I have found many philosophical and even theological similarities between evangelicalism and Thomistic philosophy that make it attractive to me as an evangelical.
Aquinas was a pre-Trentian Catholic, part of what may be called the “Old Catholic Church” with which Episcopalians would be happy on most counts. As such, Aquinas was not committed to the immaculate conception of Mary, the bodily assumption of Mary, the infallibility of the Pope, and a number of other Roman Catholic idiosyncrasies. Further, Aquinas was committed to the principle of sola scriptura, to the need for careful exposition of the Scriptures, and other doctrines characteristic of Protestantism. His basic Bibliology (minus the Apocrypha), Prolegomena, Apologetics, Theology Proper, and Christology is compatible with evangelicalism.
As a matter of fact, I find Aquinas’s philosophy to be a helpful prolegomenon for evangelical theology. After all, Aquinas defended metaphysical realism, the correspondence view of truth, propositional revelation, classical apologetics, and classical theism—all of which are helpful to defending the evangelical positions. Indeed, one has to search hard, if not in vain, to find an evangelical philosopher who can match Aquinas in these areas.
But what we know of as “Roman” Catholicism today, with its belief in works being necessary for salvation, the veneration of and prayers to Mary, the worship of the consecrated host, buying indulgences, Purgatory, adding apocryphal books (in support of praying for the dead) to the inspired Scripture, and bowing to the infallibility of the Pope, simply cannot compete with the simplicity of the evangelical Gospel: “Believe on the Lord Jesus Christ and you shall be saved” (Acts 16:31). And “Whoever hears my word and believes him who sent me has [right now] eternal life. He does not come into judgment but has [already] passed from death unto life” (John 5:24).
Similarly, many Protestants who identify closely with the writings of Saint Augustine would not think of throwing out his philosophy entirely because he claimed to be a Catholic, accepted books of the Apocrypha, believed in baptismal regeneration, and other Catholic teachings.
My attraction to Thomism is somewhat like my attraction to the writings of C.S. Lewis. There are many things I like about Lewis’s views—his apologetics, his belief in absolute truth and morals, his classical theism, his defense of New Testament miracles, his affirmation of the Virgin Birth, the Incarnation of Christ, his belief in the resurrection of Christ, eternal punishment (Hell). However, there are also some of Lewis’s beliefs which I do not accept—his denial of some Old Testament miracles, his belief that the OT contains myths and errors, his belief in evolution, and his acceptance of Purgatory. But none of these disagreements with him hinder my acceptance of the many positive values I find in Lewis. And despite my acceptance of all these positive features in Lewis, I have never been tempted to become an Anglican (as he was) or even an Episcopalian. One can profit from his positive philosophical views without buying into any of his negative religious views. Why throw the baby of truth out with the bath water of error if the name is Aquinas, Augustine, or Lewis?
Turnabout is Fair Play
While we are losing a few intellectuals out of evangelicalism to Rome, we are gaining tens of thousands of converts to evangelicalism out of Catholicism. The trade-off highly favors evangelicalism. A 2007 Pew Foundation survey revealed that Catholics have experienced the greatest net loss of any American religion. Were it not for immigrant Catholics, the percent of Catholics in America would be decreasing. In 1997 a Catholic sociologist reported that one in seven Hispanic Catholics in the USA was abandoning the church. According to World Magazine (Jan. 15, 2011), the number is nearly one in five. And it is almost one in four for second-generation Latinos. This is good news and bad news. It is bad news in that most of those who leave Rome are claiming no religion at all. It is good news for evangelicalism since 40 percent of those who leave the Roman Church are becoming evangelical. It is not just laypeople who are leaving. Several educated Catholics and scholars, including priests and nuns are leaving too.[13]
There are literally tens of thousands of Catholics in South America who have become evangelical. Based on some polling, Brazil, for example, may be 50% Catholic and 30% evangelical now. Also, tens of thousands of these Catholic converts end up in one of the large evangelical churches where they are singing God-centered praise music and being taught the Word of God. This is something that Rome, with all its layers of tradition, has lost. Once they find that works are not a necessary condition for salvation (Romans 4:5; Ephesians 2:8-10; Titus 3:3-6) but that we are saved by grace alone through faith alone, they make great evangelical Christians. They realize that we cannot work for grace but that we do work from grace. Once they learn that we can have eternal life now (John 5:24) by faith and do not have to work for it or wait until they die, they are exuberant.
Conclusion
I for one welcome the Thomistic renewal in evangelicalism. In a world of experientialism, a shot of Thomistic “rationalism” is more than welcome. Likewise, Thomism is a good antidote for the Post-Modern thought and for the New Age mysticism that has penetrated some strands of evangelicalism. In addition, the Angelic Doctor’s emphasis on objective truth and propositional revelation is a sure cure for Barthian existentialism that has infiltrated the evangelical view of Scripture. As Reformed Thomist John Gerstner put it, “God wants to reach the heart, but he does not want to bypass the head on the way to the heart.” Thomism can definitely help in this department.
Last but not least, Thomistic metaphysics is the only solid answer to the drift into Open Theism and process views of God. Of course, Rome is not home soteriologically (salvation) or ecclesiologically (church), but Thomism does embrace important truths in Prolegomena, Apologetics, Theology Proper, and Metaphysics—truths which evangelicals desperately need today. In brief, there is too much good in Aquinas’s views to be singing “Should Old Aquinas be Forgot!”
[1] See Chapter 8 of Norman L. Geisler and Joshua M. Betancourt, Is Rome the True Church? A Consideration of the Roman Catholic Claim (Wheaton, IL: Crossway, 2008).
[2] Ibid.
[3] See Norman L. Geisler and Ralph E. MacKenzie, Roman Catholics and Evangelicals: Agreements and Differences (Grand Rapids, MI: Baker Books, 1995).
[4] Thomism here seems to be conceived of mainly as a moderate realist system of metaphysics and epistemology. It seems to not encompass all of Aquinas’s views of nature, grace, salvation, sacraments, and more. In Distinguish to Unite, or The Degrees of Knowledge, which Dr. Geisler cited favorably in other chapters, Jacques Maritain argues similarly that Thomistic philosophy can and should be applied outside of the context of Roman Catholicism. – Editor
[5] Norman Geisler, Thomas Aquinas: An Evangelical Appraisal (Arlington, TX: Bastion Books, 2025), Chapter 5.
[6] Augustine, De fide rerum quae non videntur.
[7] Thomas Aquinas, Summa theologiae, P. 1, Q. 1, 5.
[8] Ibid.
[9] Ibid.
[10] Thomas Aquinas, Quaestiones disputatae de veritate, Q. 14, Art. 1.
[11] Ibid., emphasis added.
[12] Christopher A. Castaldo, Holy Ground: Walking with Jesus as a Former Catholic (Grand Rapids, MI: Zondervan, 2009).
[13] See https://bereanbeacon.org/resources/. Bennett and Diehl, On the Wings of Grace Alone: The Testimonies of Thirty Converted Roman Catholics; Bennet, Far From Rome, Near to God: Testimonies of 50 Converted Catholic Priests; Bennett and Hertel, The Truth Set Us Free: Twenty Former Nuns Tell Their Stories of God’s Amazing Grace.
Dr. Geisler is the author of Thomas Aquinas: An Evangelical Appraisal (Bastion Books: 1991, 2025), What Augustine Says (Bastion Books: 2013), Is the Pope Infallible: A Look at the Evidence (Bastion Books:2012), Is Rome the True Church? A Consideration of the Roman Catholic Claim (Crossway Books:2008), and Roman Catholics and Evangelicals: Agreements and Differences (Baker Academic:1995). For additional resources by Dr. Geisler on Roman Catholicism, please visit http://normangeisler.com/rcc/
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