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Philosophy Questions: What Is Christian Philosophy?

Photo of Daniel McCoyDaniel McCoy | Bio

Daniel McCoy

Daniel is happily married to Susanna, and they have 3 daughters and 2 sons. He is the editorial director for Renew.org as well as an online adjunct instructor for Ozark Christian College. He has a bachelor’s in theology (Ozark Christian College), master of arts in apologetics (Veritas International University), and PhD in theology (North-West University, South Africa). His books include the Popular Handbook of World Religions (general editor), Real Life Theology: Fuel for Effective and Faithful Disciple Making (co-general editor), Mirage: 5 Things People Want From God That Don't Exist, and The Atheist's Fatal Flaw (co-authored with Norman Geisler).

What is Christian philosophy? As the “love of wisdom,” philosophy is thinking hard about life’s biggest questions of what’s real, true, and good. Christian philosophy is thinking hard about life’s biggest questions from a Christian perspective. Some of the greatest Christian philosophers throughout history include the medieval thinkers Augustine and Thomas Aquinas. 

Christians conversing with philosophers is one thing. Christianity conversing with philosophy is quite another. As for conversing with philosophers, Paul made such an impression on the Stoics and Epicureans in the Areopagus in Athens that at least four of the philosophically minded responded to Paul’s invitation seemingly on the spot (i.e. “Dionysius . . . Damaris . . . and others” according to Acts 17:34). Philosophy can only get you so far, and these people had found something better in the gospel Paul was sharing.

But after two or three generations, Christian thinkers had the luxury to ask a more complicated question than how to convert philosophers to Christ: how should Christianity relate to philosophy? We already knew that Christianity cannot be reducible to mere philosophy. Does that then mean that the two must remain completely separate? Yet, all we have to do is list the big philosophical questions in order to see that Christianity and philosophy will overlap at many points: What is truth? What is real? What does it mean to be human? How should we live? What is a just society? Is there a God?

Let’s dive into what would be involved in doing “Christian philosophy.”

How Philosophy Relates to Christianity

The Bible isn’t structured in order to give a systematic answer to each question. Yet Christianity is also not neutral on the big philosophy questions. The puzzle isn’t if Christianity overlaps with philosophy, but how. In particular, the puzzle is whether Christianity answers these questions through divine revelation (e.g., the Bible) alone, or whether Christian “philosophizing” also plays a part. I’m going to suggest that Christian philosophizing is a helpful tool in answering these big questions.


Christian Philosophy: “Christian philosophizing is a helpful tool in answering these big questions.”


Here’s something of a backstory to Christian philosophy: The church was not born to the sound of applause. Christians had to learn how to defend their religion and their rights to practice it. So there arose “apologists.” An “apologist” was someone who defended their Christian faith and made a case for Christianity being true and good.

Some of these apologists mistrusted philosophy, while others, often converted philosophers themselves, credited philosophy for preparing them for the gospel. The former included Tertullian (ca. 155-220) who famously quipped, “What indeed has Athens to do with Jerusalem? What concord is there between the Academy and the Church? What between heretics and Christians?”[1] The latter included Clement of Alexandria, who believed that philosophy prepared the Greeks to hear the Gospel similarly to how the Law of Moses prepared the Jews (“a schoolmaster to bring ‘the Hellenic mind’ as the law, the Hebrews, ‘to Christ’”).[2]


Christian Philosophy: Philosophy was “a schoolmaster to bring the Hellenic mind…to Christ.” 


Two Extremes for Christian Philosophy to Avoid

Reason Minus Faith

We see modeled in such thinkers the crucial avoidance of two extremes. Says Tertullian, we must guard against reason minus faith. After all, hadn’t Paul asked,

Where is the one who is wise? Where is the scribe? Where is the debater of this age? Has not God made foolish the wisdom of the world? (I Cor. 1:20)

Paul had also warned,

See to it that no one takes you captive by philosophy and empty deceit, according to human tradition, according to the element spirits of the world, and not according to Christ (Col. 2:8).

Faith Minus Reason

Yet, on the other hand, Christians should also guard against faith minus reason, as thinkers like Clement of Alexandria remind us. After all, Peter had told Christians to be able to “make a defense,” giving reasons for our hope (I Peter 3:15). Paul saw one of the purposes Jesus had given him the “defense and confirmation of the gospel” (Phil. 1:7). Paul apparently believed the Christian faith to be reasonable since he regularly reasoned with nonbelievers about its truthfulness (Acts 17:2; 17:17; 18:4; 18:19; 19:8-9).


Christian Philosophy: “Paul apparently believed the Christian faith to be reasonable since he regularly reasoned with nonbelievers about its truthfulness.”


How Christianity interacts with philosophy should pitch a tent somewhere between these two extremes. Christianity wasn’t merely reasoned into existence, it was revealed. And, because it was revealed by the God whose “Word is truth” (John 17:17), we should discover it to be reasonable.

Discovering Truth from Outside

With Christianity being truthful, then wherever non-Christian philosophers stumbled upon what was likewise true, Christians felt justified in using these philosophers’ insights to complement and point to the truth of Christianity. So, even while John called out the philosophy of Gnosticism (I John 4:2-3), Paul favorably quoted a Stoic poet to make a point (Acts 17:28). While philosophers get no special exemption for being wrong, they apparently don’t need divine inspiration to be right.

An Intro to Neo-Platonism

We see this discerning of wheat from chaff with neo-Platonism. Plotinus (A.D. 205-270) left his home in Egypt to become a soldier for Rome, eventually returning to Rome to teach philosophy. Plotinus followed Plato in teaching a highest reality, but tweaked him as well: this reality was not to be accessed by reason, but by mystical experience. Moreover, instead of assuming the radical Platonic dualism of two worlds, Plotinus brought Plato and Aristotle together by using the highest reality (Plato’s world of the Forms) to explain the origination of the physical world around us (Aristotle’s emphasis).[3]


“Plotinus brought Plato and Aristotle together by using the highest reality (Plato’s world of the Forms) to explain the origination of the physical world around us (Aristotle’s emphasis).”


Plotinus’s highest reality was an unknowable, impersonal deity he called the “One.”[4] Like the sun mindlessly emitting rays, the One emanates Mind, which in turn emanates individual minds. Mind also emanates the World Soul (a concept borrowed from Plato) which likewise emanates other souls. Finally, Soul emanates Matter. The farther each entity is removed from ultimate reality (the One), the less real it becomes. Finally, beneath the lowest level of things that exist (i.e. Matter) is a final level called “nothingness.” Plotinus calls this nothingness “evil.” Evil is what holds people down, so that they remain souls imprisoned in bodies.[5] Plotinus calls evil “a fall, a descent into body, into Matter.”[6]

According to Plotinus, it’s impossible for people to conceptualize any meaningful truth about the “One.” So, the only way to connect with the neo-Platonic deity is to experience mystical union with it. This is done by retreating from one’s outer experience (Matter) into one’s inward experience (Soul), a retreat which is achieved through asceticism. From there, one ascends from the inner Soul to the upper world of Mind through meditation. Finally, one ascends from Mind to the One through mysticism.[7]

Unsurprisingly, the followers of Plotinus saw his system as a way of salvation. As such, it was a clear rival to Christianity. Its god had no initiative to take. Involuntarily emanating oneself is quite a bit less intentional than how the God of the Bible picked a day on the timeline in which to incarnate himself.[8] Despite clear contrasts, early Christian thinkers still borrowed terms from neo-Platonism, all the while seeing non-Christian philosophy’s role as more preparation for, not partnership with, the gospel message.


“Early Christian thinkers borrowed terms from neo-Platonism and saw non-Christian philosophy’s role as more preparation for, not partnership with, the gospel message.”


Augustine and Neo-Platonism

Also from Egypt, Augustine was for a time a neo-Platonist. When the great rhetorician became a Christian, Augustine was able to use something he had learned from neo-Platonism to hurdle one of Christianity’s greatest intellectual obstacles: the problem of evil. Many people wonder why there  is evil and suffering if a good God is said to have created this world. It would seem that a good God should only create good things.

But hadn’t Plotinus made the case that evil wasn’t really a “thing”? He had said, “The lowest descent is into evil and, so far, into non-being; but to utter nothing, never.”[9] Augustine thought Plotinus’s reasoning made a lot of sense: pure evil doesn’t seem to exist in itself, but only as a corrupter or injurer of what was originally good.


“Pure evil doesn’t seem to exist in itself, but only as a corrupter or injurer of what was originally good.”


Here is what Augustine figured: Pure evil couldn’t exist by itself, because, after all, something that is pure evil would have to be deprived of all good. And this would seem to have to include being deprived of even existing, because existing is a good thing. Evil, therefore, couldn’t be an entity that God created as its own thing. Instead, evil has to set up residence in a will. And the evil will cannot have been created that way, otherwise you don’t have an evil will, but only an evil Creator (and the question of where evil came from is merely forced back a step). The evil will couldn’t have been created that way because there had to be good in the will, so that there would be something to corrupt and injure. The will becomes evil not because it is at the mercy of some preceding cause, but simply because the will wills evil.[10]

But how could evil get willed in the first place, when there was just God and his perfect creation? Well, the moment these wills were created, there came the possibility of a creature willing his own good over the Creator’s good. And to will a lesser good (i.e. the creature’s over God’s) is to will evil. We call this “pride.” Thus, pride is the root of all evil.


“To will a lesser good (i.e. the creature’s over God’s) is to will evil. We call this ‘pride.’”


Pride wasn’t a thing created by God, but was a choice made possible the moment God created an additional will.[11] In short, God didn’t create a thing called evil, nor did he create anything evil. Instead, God created wills. Here’s the irony: wills (the cause of evil) are implicitly celebrated any time anybody expresses their will that evil be eradicated in any kind of problem-of-evil argument.

Preserving Truth in Dark Ages

Augustine wrote as barbarians ransacked Rome. As the Church labored to Christianize and stabilize Europe through the early Middle Ages, Christian theologians followed Augustine’s example in philosophizing from a Christian perspective, and in so doing, adopting an appreciative posture toward philosophy, especially the branch of philosophy we call “logic.” Throughout the medieval period, Christian thinkers such as Boethius, Anselm, and Peter Abelard applied logic to Christianity to fine tune their theology. Most of these thinkers were monks and clergymen.[12]


Christian Philosophy: “Christian thinkers such as Boethius, Anselm, and Peter Abelard applied logic to Christianity to fine tune their theology.”


As the barbarian-overrun empire spun backward, much of the philosophical insights of previous eras were lost. The work of certain medieval theologians was impressive. But the rediscovery and translation of a large volume of Aristotle’s works in the 12th and 13th centuries brought about a revolution of sorts in medieval philosophy. Christian theologians were confronted with a grand philosophical system that hadn’t needed Christianity.[13] Many church officials mistrusted this infusion of ancient non-Christian texts as a godless intrusion.

Thomas Aquinas, however, saw things differently. For centuries, many of the best theologians were Muslims. Muslims had overtaken cities with some of the finest libraries (e.g. Alexandria, Syrian Antioch). As a result, Islamic philosophy was threatening to overtake European thought. Thomas Aquinas wanted to develop a Christian theology so robust that it could arrest Islam’s intellectual advance.[14] With the help of Aristotelian philosophy, Aquinas would construct one of the greatest intellectual systems the world has seen.


Christian Philosophy: “With the help of Aristotelian philosophy, Aquinas would construct one of the greatest intellectual systems the world has seen.”


Aquinas’s Synthesis of Philosophy and Theology

Aquinas knew that, given the truthfulness of Christianity, true philosophy could never contradict it. But this wasn’t as simple as merely saying that all philosophy that said anything against Christianity was automatically false because of its impious conclusions. Instead, Aquinas recognized philosophy as a valid study in its own right. If philosophical conclusions were to be proved wrong, they would have to be proved wrong using philosophy itself.[15]

So, for Aquinas, philosophy and theology become allies with each side respecting the other’s jurisdiction. So far so good. But the crucial clause in the above paragraph is “given the truthfulness of Christianity.” Is the Christian message logical? Largely, Christianity’s believability hinges on whether or not there are good reasons to believe the Christian God exists.


Christian Philosophy: “Christianity’s believability hinges on whether or not there are good reasons to believe the Christian God exists.”


Regarding this question, medieval theologians hadn’t been idle. Recall Aristotle’s own argument: what else could actualize all the world’s potentialities except for something that simply is pure actuality? Likewise, theologians such as Augustine, Anselm, and Aquinas pointed to all sorts of phenomena they believed were logically traceable back to the existence of the all-good, all-powerful God of Christianity, such as:

  • Where could unchanging truths originate except in some kind of Mind?
  • We can set a Hitler beside a Mother Theresa and discern which would be the more moral person. How can we have such discernment apart from a perfect standard of goodness to which people align for better or worse?
  • How did motion get going?
  • What explains the apparent purposefulness of the world?
  • Where does the very idea of God come from, and since God is the greatest conceivable being, isn’t a God existing in reality greater than one existing merely as an idea?
  • Since nothing in the universe necessarily had to exist, why does it?
  • Which more logically caused all the effects we see around us: causes going back in an infinite regress or something that was itself uncaused and was simply there?

Christian Philosophy: “Convinced that it was reasonable to believe God exists, Aquinas felt justified in constructing his theology by synthesizing biblical exegesis with the best philosophical insights available.”


Convinced that it was reasonable to believe God exists, Aquinas felt justified in constructing his theology by synthesizing biblical exegesis with the best philosophical insights available (thanks to the rediscovery of Aristotelian philosophy). His synthesis owed much to the distinction between what something is (its “essence”) and that something is (its “existence”). Aquinas concluded that God is the only being whose essence is existence. God is being, while all His creatures have being derived from their Creator.[16] To those who question whether humans can know anything about God’s essence, Aquinas argued that it is perfectly possible to know something about an effect by looking at the cause.[17]

Of course, the Cause we’re talking about is the kind of bigness a tiny little mind can’t exactly fit within its confines. G.K. Chesterton pointed out the problem with the person who “seeks to get the heavens into his head”: “What a little heaven you must inhabit, with angels no bigger than butterflies!”[18] But at least one can aspire to get his head into the heavens.

And that’s the opportunity the human has because of the relationship between Cause and effect. As Aquinas put it, “Some likeness must be found between such effects and their causes: for it is of the nature of an agent to do something like itself.”[19] We humans—stamped with the image of God and entrusted with the Word of God—see effects like minds, goodness, wisdom, truth, creativity, and power. To describe God’s essence, we ascribe these concepts to him via analogy (what God is like), because effects are able to communicate something of what the cause is like.


Christian Philosophy: “To describe God’s essence, we ascribe these concepts to him via analogy (what God is like), because effects are able to communicate something of what the cause is like.”


The Unraveling of Aquinas’s Synthesis

Shortly after Aquinas’s seminal synthesis, theologians began tweaking it while others clearly wanted to topple it. William of Ockham takes the blame for largely unraveling what Aquinas had woven. The most effective way to do this was to attack the rational arguments given for God’s existence. Do some of these arguments show that God probably exists? Probably, conceded Ockham. Yet Ockham doubted that the arguments were totally certain, as some theologians had claimed.[20] It’s important that Christian apologists and philosophers don’t overstate their case. Aquinas was right that the arguments for God’s existence are compelling, but we should also admit that they’re not 100% certain. There’s always room for doubt.

So Ockham attacked these proofs for God’s existence. Once the legitimacy of these proofs came to be doubted, the romance between theology and philosophy soured. As time went on, with its offspring’s legitimacy questioned, theology would internalize the offense, and philosophy would take the opportunity to back out of the relationship and enjoy its autonomy. The day would come when modern philosophy would pronounce the great medieval synthesis to be in ruins, toppled like a Gothic cathedral and begging to be built over.


“Once the legitimacy of these proofs came to be doubted, the romance between theology and philosophy soured.”


For a long time, however, theology and philosophy had enjoyed a good relationship. Unless one is prepared to argue that Aquinas was completely wrongheaded (i.e., if one is prepared to admit that much hubris), then one should not rule out that possibility again. Indeed, the past decades have seen a “renaissance” of Christian philosophy, as many of the brightest philosophers in academia today are Christians.


[1] Tertullian, “Chapter VII—Pagan Philosophy the Parent of Heresies: The Connection between Deflections from Christian Faith and the Old Systems of Pagan Philosophy,” in Anti-Nicene Fathers, Vol. III, ed. Allan Menzies (Edinburgh: T&T Clark) http://www.sacred-texts.com/chr/ecf/003/0030273.htm (accessed 3 June 2015).

[2] Clement, “Chapter V—Philosophy the Handmaid of Theology,” in Anti-Nicene Fathers, Vol. II, ed. Alexander Roberts and James Donaldson (Edinburgh: T&T Clark) http://www.sacred-texts.com/chr/ecf/002/0020298.htm (accessed 3 June 2015).

[3] Frederick Copleston, Greece and Rome, in A History of Philosophy, Book One (New York: An Image Book, 1985), 467-469. 

[4] Copleston, Greece and Rome, 464.

[5] Copleston, Greece and Rome, 468-470. 

[6] Algis Uzdavinys, ed., The Heart of Plotinus: The Essential Enneads (Bloomington: World Wisdom, 2009), 71.

[7] Norman Geisler, “Plotinus,” in Baker Encyclopedia of Christian Apologetics (Grand Rapids: Baker, 1999).

[8] Copleston, Greece and Rome, 413.

[9] Uzdavinys, 218.

[10] Augustine, “Chapter 6: What the Cause of the Blessedness of the Good Angels Is, and What the Cause of the Misery of the Wicked,” in City of God: Book XII, trans. Marcus Dods, New Advent http://www.newadvent.org/fathers/120112.htm (accessed 3 June 2015).

[11] Augustine, “Chapter 8: Of the Misdirected Love Whereby the Will Fell Away from the Immutable to the Mutable Good,” in City of God: Book XII, trans. Marcus Dods, New Advent http://www.newadvent.org/fathers/120112.htm (accessed 3 June 2015).

[12] Colin Brown, “Scholasticism,” in Introduction to the History of Christianity, ed. Tim Dowley (Minneapolis: Fortress Press, 2002), 286-287.


Christian Philosophy: “The past decades have seen a renaissance of Christian philosophy.”


[13] Frederick Copleston, Ockham to Suarez, in A History of Philosophy, Book One (New York: An Image Book, 1985), 414.

[14] Norman Geisler, “Thomas Aquinas: Christian History Interview—He’s Our Man,” in Christianity Today (Issue 73, 2002) http://www.christianitytoday.com/ch/2002/issue73/13.43.html (accessed 3 June 2015).

[15] Frederick Copleston, Ockham to Suarez, 415-416.

[16] Frederick Copleston, Augustine to Scotus, in A History of Philosophy, Book One (New York: An Image Book, 1985), 309.

[17] Norman Geisler, Introduction and Bible, Systematic Theology (Minneapolis: Bethany House, 2002), 146-147.

[18] G.K. Chesterton, Orthodoxy (Colorado Springs: Water Brook Press, 2001), 15, 20.

[19] Thomas Aquinas, “Chapter XXIX: How Likeness to God may be found in Creatures,” in Summa Contra Gentiles, trans. Joseph Rickaby http://www3.nd.edu/Departments/Maritain/etext/gc1_29.htm (accessed 3 June 2015).

[20] Copleston, Ockham to Suarez, 12.