Introduction to Systematic Theology

Hello and welcome to the second module of Faith Seeking Understanding. The goal of Faith Seeking Understanding is to equip Christians to develop a biblical worldview, grounded in God’s plans and purposes as revealed in the scriptures, integrated with insights into his creation discovered through various human disciplines, for the sake of knowing and serving him better.

We spent last term thinking together about biblical theology—and if you weren’t with us for that, we did record it all, as we’re doing for this one, so as soon as we get it all up and running you can get the recordings from our website, faithseekingunderstanding.co.za.

This term we’re thinking together about systematic theology. We’ll be thinking this week about what it is, why we should do it, and some of what’s involved in systematic theology as a discipline. From there, we’ll be spending weeks 2–5 actually doing systematic theology, thinking together about the doctrine of God. The goal is simple: to Know Thy Maker, which is what we’ve called this module. We’ll be looking at four aspects of God over the course of this module: the doctrine of creation, providence, simplicity, and eternity.

Now, there is a big gap in our module: the Trinity. We’ll make passing reference to the Trinity throughout, but we’re not actually going to be spending any time looking at the Trinity itself. This isn’t because we forgot; nor is it because we don’t think it’s important—even central—to our understanding of God. Actually it’s for those two reasons that we’re not covering the Trinity in this module: the Trinity is so vast and so central that we’re actually planning on having a module on the Trinity all by itself some time in the future.

The remainder of this first session is going to be spent thinking about systematic theology, but just one last point before we do: in talking about systematic theology there’s the danger of leaving it all in the abstract or the conceptual. It’s very easy to talk about ideas and simply leave them as ideas. We don’t want that to be the case with Faith Seeking Understanding—again, our goal is to equip Christians to develop a biblical worldview, grounded in God’s plans and purposes as revealed in the scriptures, integrated with insights into his creation discovered through various human disciplines, for the sake of knowing and serving him better. So in each talk, our plan is to include a point of connection where the doctrine we’re talking about that week connects with real life.

Defining systematic theology

Systematic theology is combining what we can know from scripture with what we can know from nature, to build a system of thought about God and his creation.

Now, there are three things that characterise how we’re going to be talking about systematic theology.

Unity

Last term Roland showed us this diagram:

At the bottom we have exegetical theology. This is looking at the individual sections of the Bible, working hard to understand them on their own terms, in their historical context, trying to get into the head of the original author and work out what it is that they meant. The next layer up is what we spent last term thinking about: biblical theology. Biblical theology, we said, is the study of God’s plans and purposes as they are revealed progressively in his dealings with humanity. What sets biblical theology apart from exegetical theology is the overarching unity. It’s taking the Bible as one unified story, looking at how it unfolds over the course of the Bible story.

Systematic theology is where we come to this term, which is the next stage of unity. The unity we have in systematic theology is different from that of biblical theology; it’s more absolute, in a sense. In biblical theology we see the overarching unity as the story unfolds, but a kind of disunity, in that earlier parts of the story may not be the same as later parts (at least not in every respect). Systematic theology, on the other hand, has a more timeless, unchanging unity. One scholar puts it this way: “In Biblical Theology the principle is one of historical, in Systematic Theology it is one of logical construction. Biblical Theology draws a line of development. Systematic Theology draws a circle.”

For example, as the Bible story unfolds we find that, while we’re introduced to one God, that God is triune. We see this come out in a number of passages as we do exegetical theology. We see this progressively revealed through the overarching storyline of the Bible as we do biblical theology. But obviously this isn’t just true in the parts of the Bible we read about it; it’s true of God always. It’s a truth that doesn’t depend on where we are in time, or on what else might be going on.

It’s that sort of timeless unity that is characteristic of systematic theology, and it’s in this way that systematic theology is seeking to articulate truths about God and his creation. That’s the goal; but, given the diversity in how God has revealed himself to us, how do we get there?

Organisation

Here we’re taking stock of what we have to work with, and organising it into a system. We’re taking the work we’ve done in exegetical theology and biblical theology, and seeing how they fit together into a conceptual framework. It’s a matter of working out the common threads and drawing them together. It’s working out a framework where we can weigh up everything we know, see how it’s all interconnected, and from there work out how it should be articulated. So, as you can see in the diagram, we take various passages, interpreted individually and together using exegetical and biblical theology, to come to how God has revealed himself in special revelation (scripture), and thus come to unity—being able to articulate the doctrine in a timeless, absolute sort of way.

To illustrate, let’s carry on thinking about the Trinity. The doctrine of the Trinity is fundamental to what it means to be a Christian. But we’ll never come across the word “trinity” in the Bible. What the church had to do in its first few hundred years, then, was to work out how best to articulate what we believe about God.

So first we have to weigh up the biblical data. For instance, we have passages like John 5, which has in its context the assumption shared by Jews and Christians alike that there is only one God, but from Jesus’ words we can infer that Jesus is God; and we have passages like 1 Corinthians 2, which says that “the Spirit searches everything, even the depths of God” (v. 10, HCSB), from which we can infer that the Holy Spirit is God.

Then we organise it into a conceptual framework, and when we look at it all together, we see that: 1) there is one God; 2) there are three Persons in God; and 3) each of those Persons are fully God; and we have various texts to support each of those points.

We get all of that from various passages of scripture, Old and New Testaments. But, while the Bible is clear on all three of those things, the Bible doesn’t tell us how that’s all meant to hang together—that simply wasn’t what the biblical authors were trying to do. One scholar puts it this way: “The doctrine of the Trinity is a conceptual framework that allows us to read every biblical text (concerning God’s life) with due seriousness, but without discovering contradictions between them.”

Our doctrine of the Trinity, then, is a prime example of systematic theology: setting out a framework in which we can hold different parts of scripture together to give us a holistic picture of what the Bible teaches about a particular subject.

Combination

Systematic theology is combining what we can know from scripture with what we can know from nature, to build a system of thought about God and his creation. The next thing we want to focus on in our definition is this: combining what we can know from scripture with what we can know from nature.

So far we’ve only filled out one side of that: what we can know from special revelation—from scripture. But we could also talk about what we can know about God and his creation from general revelation—or from nature.

Excursus on nature and philosophy

Now, when I say “nature,” I’m not thinking about taking a walk in your garden and appreciating the fact that God made all of it in its beauty and complexity, and how incredible God is for the variety we see in the flowers and animals and how it all seems to be bursting with life… It might include all of that, but it isn’t just that.

Rather, what we mean by “nature” is what we can know naturally as opposed to supernaturally. It’s what we can know about God and his creation from the natural order of things. “What we can know from nature,” then, is a way of talking about what we can learn about God and his creation by looking at the ordinary ways in which things work. That might include a walk in the garden, but it’ll also include insights from other disciplines, especially from philosophy.

Philosophy, as one writer has defined it, is “a peculiarly stubborn effort to think clearly.” Philosophy is the quest to discover what lies beneath the surface. It’s talking about those base principles that govern the way everything works. It’s a way of talking about the most fundamental realities of the universe in the most precise ways we can manage.

When we talk about philosophy today that’s typically what we mean, but focused specifically on questions about existence, knowledge, logic, and ethics. But it wasn’t always thought of in that way. Philosophy for the ancient Greeks would have included many things that have since become their own disciplines—things like psychology, mathematics, biology, economics, and so on. But as there was more to say about these various topics they split off and became disciplines in and of themselves. As one writer has put it: “One effect of these shifting boundaries is that philosophical thinking can easily seem to be unusually useless, even for an intellectual enterprise. This is largely because any corner of it that comes generally to be regarded as useful soon ceases to be called philosophy.”

When we talk about philosophy we’ll primarily be talking about the narrower definition more commonly used today. But it is worth saying that natural theology can include philosophy in his broader sense, including insights from psychology, science, biology, and so on.

Nature and systematic theology

So how does this fit in with systematic theology? Systematic theology is taking what we can know about God and his creation from what he has told us in scripture, but also from the world around us—from nature. “The heavens declare the glory of God; the skies proclaim the work of his hands” (Ps. 19:1, NIV).

18 The wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who by their unrighteousness suppress the truth. 19 For what can be known about God is plain to them, because God has shown it to them. 20 For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So they are without excuse (Rom. 1:18–20).

In Acts 17, Paul is talking to a group in Athens and he quotes their poets back to them:

26 [God] made from one man every nation of mankind to live on all the face of the earth, having determined allotted periods and the boundaries of their dwelling place, 27 that they should seek God, and perhaps feel their way toward him and find him. Yet he is actually not far from each one of us, 28 for “In him we live and move and have our being”; as even some of your own poets have said, “For we are indeed his offspring.” (Rom 17:26–28).

As Protestants we tend to focus all our attention on the one book. Wayne Grudem is a good example of this. He opens his Systematic Theology by defining systematic theology as “any study that answers the question, ‘What does the whole Bible teach us today?’ about any given topic.” He intentionally limits his focus primarily to special revelation. He does say this is just his emphasis, and that he will include other disciplines like philosophy along the way. Nevertheless, they way he’s defined systematic theology on the outset as how the Bible answers various questions says something about how he’s chosen to limit his scope. In a similar vein, John Frame defines theology as the “the application of Scripture to all areas of human life. Exegetical, biblical, and systematic theology look at the whole Bible from various perspectives.” Again, what’s quite clear is a sort of single-minded focus on special revelation.

Now, this isn’t a heavy criticism. The Bible is vast enough that that can be an entire discipline in and of itself. But this approach seems to me to be quite typical of Reformed evangelicals: our focus is on the book of scripture, while the book of nature lies on the shelf, gathering dust. Part of this, I think, has to do with the Reformation cry: Sola Scriptura—Scripture alone! But when we crack open our Bibles and find verses the ones we just read, it should be clear that there is another book. And maybe, instead of just letting it gather dust on the shelf, it’s time that we pick it up and read it. What we’re trying to do is to understand reality—what we can know about God, not just from scripture, but from all of reality, and for that we need philosophy.

I remember talking to somebody about the relationship of theology and philosophy, and he said something to the effect of, “It’s cool to use philosophy in theology, as long as it doesn’t go too far.” I’m not entirely sure what he meant by “too far”—and when I pushed him on it I don’t think he was entirely sure either—but I think it was something to the effect of giving philosophy so much sway that our theology is compromised.

If we’re willing to reject truths that are plainly taught in Scripture because of what we learn from philosophy, then yes, that’s a problem. But I also think that’s just doing bad philosophy. All truth is God’s truth. If we’re doing philosophy properly, it won’t contradict Scripture. If we find that it does, it’s probably a sign that we’ve done something wrong and need to go back and check our work.

None of that is to say that both books are on equal footing. We should be clear that, while God has revealed himself in both ways, we only take scripture to be infallible.

Organisation in general revelation

So we have two sides to our diagram: special revelation on the one hand—the book of scripture; and general revelation on the other—the book of nature, or, as we’ve just seen, philosophy. Again, as with special revelation, a key feature of this is organisation. Except now, rather than drawing from various passages of scripture in exegetical and biblical theology, we’re talking about various concepts.

Combination, then, is the step where we take what we can know from scripture and what we can know from nature and combine it so as to reach the unity we were talking about earlier.

So, to come back to the example we’ve been using: if on the side of special revelation we’re taking what we know about the Trinity from biblical texts like John 5, which talks about Jesus being God, and 1 Corinthians 2, which talks about the Holy Spirit being God, we can now fill it out with the other side: on the side of general revelation we have concepts like substance and person, taken from philosophy.

Philosophy, then, has a crucial role in systematic theology. A moment ago we spoke about Wayne Grudem limiting his focus in his Systematic Theology to what the Bible has to say about a given topic. But notice how, when he talks about the Trinity, he can’t avoid using philosophical categories. As much as we might try to do systematic theology without philosophy, we’ll inevitably end up appealing to it at some point. Paul Helm writes that “there is an inevitable intertwining of theology and philosophy at the systematic theological level. The ordering of theological claims, and an understanding of the claims themselves, requires the use of philosophical tools.”

Systematic philosophy

So we’ve seen there are two books. We have two sides to our diagram: special and general revelation. On the one side, doing systematic theology properly depends on good exegesis, and good biblical theology. On one level this should be obvious: to properly know God we need to pay proper attention to how he has revealed himself. That’s why we spent five weeks thinking together about biblical theology last term: understanding God by faithfully interpreting his self-revelation in scripture is crucial.

Whether or not you joined us for our first module of FSU, for most of us, we will have studied the Bible, perhaps in some depth; but philosophy, not so much. As we’ve said already, good systematic theology depends on good exegesis and good biblical theology. So for the rest of this talk we’re going to spend some time sketching out some key philosophical principles that we’re going to be making use of as this module progresses.

Actuality and potentiality

The first set of principles we’ll be looking at are actuality and potentiality. Actuality and potentiality are foundational to reality. Pretty much everything comes down to a question of actuality and potentiality.

A good place to start is to think of actuality and potentiality in terms of change. Just think for a moment: how would you define change? What is change? These are the kind of questions philosophers fill their time thinking about—as we’ve heard it defined already, philosophy is “a peculiarly stubborn effort to think clearly.” The question of what change is is one that occupied the time of a famous dead guy named Aristotle. But to understand what Aristotle thought about the matter, we first need to meet two other famous dead guys.

The first is Parmenides. Now, Parmenides didn’t believe change existed at all. Think, for example, of a cup of tea. You drink half of your tea, put it down somewhere, and forget about it, and it goes cold (something which happens to me regularly). For Parmenides, what that entails is the coldness of the tea coming into being, and the hotness of the tea going out of being. But for the coldness to come into being it would mean that something is coming out of nothing, which is impossible. Therefore change must be impossible. Now, our experience tells us that’s obviously wrong, but Parmenides simply answered that our experience is just an illusion. We might experience something as change, but that doesn’t actually make it change. And when we reason it out, says Parmenides, what we see is that change can’t actually be a thing.

The second famous dead guy we meet is Heraclitus. If Parmenides said that there’s no change, Heraclitus took the opposite extreme and said that there’s only change. Heraclitus famously said that you can’t put your foot in the same river twice—by the time you put your foot back in, the water has moved on, and it’s a different river. Again, experience tells us otherwise; it does seem like a lot is in flux in the world. Heraclitus seems more right than Parmenides. But everything? Always?

Between these two guys Aristotle walked a middle road. Both of the other two only got it half right. Change does exist; but so does rest. Where Parmenides goes wrong is in insisting that change entails something coming out of nothing—that the coldness of the tea must have come out of nothing. According to Aristotle, even if the tea isn’t cold yet, the coldness is there in the tea in a way: it’s there potentially.

The idea of potential isn’t foreign to us. We might say that walking down a particular road late at night is potentially dangerous; or that situation has the potential to go horribly wrong. We talk about somebody unlocking their potential. Really what we’re talking about is possibility or capability. In talking about a thing’s potential, we’re talking about what it could be.

A thing can have loads of potentialities; but we should note that a thing doesn’t have just any potentiality. A thing’s potential is relative to its nature—in other words how a thing could be depends on what that thing is. The tea has the potential to get cold, or to be spread all over the floor if spilled, or to be absorbed by your intestines if you drink it (I think—that’s what a quick Google search told me). But it doesn’t have the potential to, say, paint a picture, or to understand typology—which, if you were with us for our biblical theology module refers to those people, events, and institutions which reach their fulfilment in their antitype by way of analogical correspondence, and eschatological escalation. Tea can’t do any of that—and we wouldn’t expect it to; it’s not in its nature. And, of course, that will be different for different things. A thing’s potential is relative to its nature.

That’s what we mean by potentiality. With that now in the bank, we can come back to what change is: change, according to Aristotle, is the actualisation of a potential—when the tea that was potentially cold becomes actually cold.

Again, “actual” is not a foreign word to us. How something is actually is how it is in reality. So we might say it’s actually raining; or the table is actually holding that cup of tea a metre above the ground. It’s worth saying that once a thing has moved from potentiality to actuality, it’s no longer potential with regard to that thing—once the tea’s potential to be cold is actualised, it is no longer potentially cold. For it to be both potentially and actually cold would mean that it’s both cold and not cold at the same time, which doesn’t make sense. But the (actually cold) tea does have a whole lot of other potentialities—to be spilled all over the floor if spilled, to be absorbed by the intestines if drunk, or perhaps to be hot if microwaved.

This gives us an answer to Heraclitus. Remember, for Heraclitus all there is is change—or, in Aristotelian terms, there’s only potentiality. For Heraclitus, “Change and change alone is real—the implication being that there is no stability or persistence of even a temporary sort, nothing that corresponds to Aristotle’s notion of being-in-act[uality].”

So change is the actualisation of a potential. Nothing about that definition radically changes how we think about change—it’s still just that it was this, and now its that. All we’re doing is talking about it in a more precise way, because that will help us take the next few steps, which in turn will help us think more precisely about God and his creation.

But potentiality and actuality don’t only have to do with change. We don’t only use potentiality and actuality to talk about things moving from one state to another, but also to talk about how things are the way that they are moment by moment. In other words, we don’t only think about potentiality and actuality in terms of becoming, but also being.

Think again about the tea. We can actualise the tea’s potential to be on the table. Its potential to be there is actualised by the table it’s been put on. But that’s not a once-off thing—the tea’s potential to be there is only actualised for as long as the table is there, or until its potential to be somewhere else is actualised. So we can talk about something in terms of potentiality and actuality not only as it moves from potentiality to actuality, but also as, moment by moment, its potentiality is continually actualised.

Essence and existence

The next set of principles we have to talk about are essence and existence. Again, these words probably aren’t new to you—as we did with actuality and potentiality, we’re using familiar concepts in a more technical way to help us to talk more precisely about reality, which, again, will help us as we go on.

“The essence of a thing is its nature, that whereby it is what it is.” It’s a description of what makes a thing that thing at a fundamental level. Again, probably not a new word. We talk about the essence of what someone is saying—in other words, what their argument fundamentally boils down to. We might talk about the essential features of a thing—those features without which it wouldn’t be that thing.

An example that’s often used is the essence of a human. Aristotle famously defined a human as a rational animal. That, according to Aristotle, is fundamentally what a human is—its essence. And its by virtue of its essence that humans do what is distinctive about humans. Humans are rational animals—we have the essential features of what it means to be an animal (as opposed to, say, a plant), plus the additional property of rationality. The ability to reason is intrinsic to what a human is (even if for some humans it’s very deeply buried).

When we talk about the essence of a thing, we’re not talking about the thing itself; the essence of a thing is just a description of what fundamentally makes a thing that thing. One scholar explains: “Essence is not a substance …; essence is that in (or of) a substance by which the being (esse) of the substance is measured, limited, determined, defined.” For an essence to be realised in the world we need our second principle: existence.

If essence is the what-ness of a thing, existence is the is-ness of it. Again, this is not a new concept to us: we know what it is for something to exist. You know what I mean when I say that Roland exists, or when I say that Santa Claus doesn’t exist.

Everything around us has an essence, and that essence is joined with existence. In anything that exists, you can’t have one without the other. As one scholar explains: “of every being two questions are raised: ‘Is it?’ and ‘What is it?’ These questions are as irreducible as their answers. To one who asks what is man we do not answer by saying that men actually exist; and to one who asks if men exist it is not at all opportune to answer that man is a rational animal.” They’re two distinct principles; but in anything that is, you can’t have one without the other.

We said earlier that actuality and potentiality is foundational—that pretty much everything comes down to those two principles.

The same is true of essence and existence. On one level, essence and existence is another way of expressing actuality and potentiality. Essence corresponds to potentiality, while existence corresponds to actuality. We can grasp the essence of a potato, but unless its potential for existence is actualised, we don’t have an actual potato. “The creature as a ‘being’ (ens) or actual substance is what exists after the principle of essence (as [potentiality]) has received the principle of existence (as its actuality).”

Conclusion

Systematic theology is combining what we can know from scripture with what we can know from nature, to build a system of thought about God and his creation. That means working hard to interpret scripture correctly. And that means combining what we can know from scripture with what we can know from nature about God and his creation.

With that definition in place, much of what we spoke about tonight was on the side of nature. I realise that quite a bit of that is quite abstract, but we’ll be spending the coming weeks making it more concrete as we cash out these principles and build on them as we think together about a doctrine of God. The goal is unity: timeless statements we can make about God and his creation that accurately describe the way things are, for the sake of knowing God better and loving him more.