Excursus on Natural Theology (Part 1): Belief In God As Properly Basic

August 18, 2015

Reformed Epistemology

Today we are turning to a new section in our survey of Christian doctrine. We are in the midst of the study of the doctrine of God. We have completed our subsection on the attributes of God. Now I want to turn to an excursus on natural theology. We are going to leave our doctrinal outline and take an excursus into the subject of natural theology.

What is natural theology? Natural theology can be defined as that branch of Christian theology which seeks to explore the justification of Christianity's truth claims apart from the resources of authoritative divine revelation. It explores what warrant there is for Christian truth claims without appealing to authoritative inspired Scripture. Scripture might still be appealed to as simply human historical documents for historical information, but they will not be taken as authoritative or revelation from God. Natural theology, as the name suggests, is what we can learn about the existence of God apart from the resources of authoritative divine revelation.

One might ask how are the arguments of natural theology to be related to general revelation? You will remember in our study of the doctrine of revelation we saw that God has revealed himself both generally in nature and conscience as well as specially in his Word and in Jesus Christ. Through God’s general revelation in nature and conscience we can have a general knowledge of God as the Creator and Sustainer of the universe.

Are the arguments of natural theology the same as general revelation? I don’t think so. God’s general revelation is his self-disclosure in the created world that he has made. They are, as it were, the fingerprints of the potter in the clay or the telltale traits of the artist in the painting he has made. It is his self-disclosure to us in the created order. Natural theology is the result of human reflection upon the created order and upon God’s general revelation. The arguments of natural theology are human constructs. These are not divinely given. Therefore, they are fallible and could well be unsound. Every generation will be called upon to refurbish and update and develop arguments for God’s existence based upon the knowledge that they have. So natural theology is not static. It is an evolving project that is constantly renewed.

Therefore, you can feel free to disagree with any of the arguments that are shared in this section on natural theology. These are not divinely given. If you think that these are weak or poor arguments, feel free to reject them. But I hope that you will think that at least some of these arguments are pretty good arguments for God’s existence.

There has been a renaissance of interest in the subject of natural theology over the last half century or so in Anglo-American philosophy. As a result of the renaissance in Christian philosophy that has been taking place over the last several decades, there has also been renewed interest in the project of natural theology – of developing arguments for God’s existence. In fact, I see here on the shelf one such manifestation of that interest. This is the Blackwell Companion to Natural Theology published by Wiley-Blackwell in Oxford in the UK. This is a volume as you can see of considerable size that contains essays by some eleven different philosophers on different arguments for God’s existence. This is some of the most sophisticated natural theology that is available today. This is not a book for beginners.[1] If you are a beginner, you can start with something like On Guard. But this is one for professional philosophers, theologians, and scientists.

In our study in this class, we are going to study principally five arguments for God’s existence that I have worked upon personally and have defended and find especially interesting. But as the Blackwell Companion indicates, there are many more as well.

In studying natural theology I want to emphasize the importance of developing a cumulative case for the existence of God. We shouldn’t think that the existence of God depends upon the force of any single argument. Rather we ought to think of the arguments as providing cumulative evidence. Each argument reinforces the others so that the cumulative case for God’s existence, I think, is very strong. This is important because even if an argument taken in isolation is not a very strong argument, nevertheless, it could be part of a cumulative case for God’s existence that would warrant belief in God. I think the perfect analogy here will be a case built in a court of law where the prosecution will bring all manner of evidence to try to show that the accused is guilty. Any single piece of evidence might not be convincing. The fingerprint evidence could be explained away. The eyewitness testimony may not be decisive. Perhaps they can identify a motivation that would have led the person to commit the crime but that alone wouldn’t serve to convict. Nevertheless, taken together the cumulative force of all of these considerations could make it beyond a reasonable doubt that the accused is guilty.

In exactly the same way, these arguments should not be just considered in isolation but rather as part of a cumulative case. For example, the ontological argument may strike you as based upon a premise that is reasonable and plausible but it is not one you might think for which you have a compelling reason to believe. You could just as easily perhaps deny it. Or you might think that the cosmological argument from the beginning of the universe taken alone wouldn’t prove that God exists but perhaps taken in conjunction with the argument from the fine-tuning of the universe, the combination of the beginning of the universe and its incredible fine-tuning would lead you to think that it is more plausible than not that a personal creator and designer of the universe exists. You might think that the moral argument alone might not make it sufficient to believe in God, but you might think that the moral argument taken in conjunction with the argument from contingency and the ontological argument present a good case for belief in God.

So don’t think of the arguments of natural theology as links in a chain. A chain is only as strong as its weakest link. Rather, think of the arguments of natural theology as a coat of chain mail where the coat of mail is stronger than any single link because all of the links reinforce each other so that the coat of mail can be very strong even if there are individual links in it that are weaker.

Nevertheless, in presenting these arguments, it seems to me that if each argument can be shown in isolation to be a good argument for God’s existence then your cumulative case is going to be all the more powerful. Right? If the DNA evidence is decisive for the guilt of the accused and you’ve also got independent eyewitness testimony from people who were in a position to see what happened and you’ve got, say, video evidence from the recorder of the person actually committing the crime, any one of these would be sufficient for conviction. Taken together, they make a really overwhelming cumulative case.

What I’ve tried to do in defending these arguments is to consider them in isolation and show how each one, even taken alone, is a good argument.[2] Then so much the stronger when part of a cumulative case.

I formulate the arguments deductively for the case of simplicity and clarity. That is to say, I formulate them in terms of some simple premises which then lead logically to a conclusion. The advantage of doing it this way is, as I say, it makes them very simple to grasp, makes them easy to memorize and use, and it makes them very clear. You can ask the person who is skeptical of them which premise he rejects and why because if he can’t identify a false premise then if the argument is logically valid he has got to agree to the conclusion.

In these deductive arguments, what we have to do is to formulate arguments that will meet a number of conditions for being a good argument.

First of all, the argument needs to be logically valid. That is to say, the conclusion needs to follow from the premises according to the rules of logic. There are only about nine basic rules of inference that govern all reasoning. We can construct arguments for God’s existence using these rules of logic to derive conclusions. A good deductive argument would need to obey the rules of logic – it needs to be logically valid.

In addition to that, the argument also needs to be sound. That is to say, the premises of the argument need to be true. It is not enough just to have a logically valid argument; it also needs to have true premises. If you have an argument which obeys the rules of logic and has true premises then it is guaranteed that the conclusion is true. The conclusion necessarily follows by the rules of logic from the true premises and therefore is also true.

But it is not enough just to have a valid, sound argument. The premises also need to have some sort of warrant for us or some sort of evidence for us whereby we know that they are true. Otherwise, it is trivially easy to formulate arguments for God’s existence. For example, you could have an argument like this:

1. Either the moon is made of green cheese or God exists.

2. The moon is not made of green cheese.

3. Therefore God exists.

That is a sound deductive argument. Each of the premises are true. Either the moon is made of green cheese or God exists. Since God does exist that premise is true. For a disjunction to be true only one of the either-or statements need to be true. The second statement is true – the moon is not made of green cheese. Therefore it follows logically that God exists. So is this a good argument for God’s existence? I don’t think you will find it in any apologetics textbook. Why? Because the only reason you would believe the first premise is because you already believe the conclusion. The only reason you believe that either the moon is made of green cheese or God exists is because you believe the conclusion “God exists.” You are reasoning in a circle. This is called “begging the question” or “circular reasoning.”

The reason for believing the premises cannot be that you believe the conclusion, or you are guilty of begging the question. You need to have some sort of evidence for the truth of the premises (for thinking them to be true).

Here is where it gets controversial. How much evidence do you need in order to believe the premises to be true? Many times atheists will demand that you have compelling evidence for the truth of the premises. If it is even rational not to believe the premise then the argument is a failure. For an argument to be successful (they claim) the evidence must compel belief in the premises. But I think that the vast, vast majority of philosophers would say that that sets the bar for success far too high. In that case there are no successful arguments for anything of significance or importance. In order for the belief in the premises to be justified or warranted they don’t need to be certain or the evidence doesn’t need to be compelling.[3]

How strong does the evidence have to be for the premises? This is controversial. It is hard to say. Some people would say as long as the evidence is just sufficient to give you permission to believe the premises – that is enough for you to have a good argument and for your belief to be rational. If the evidence is such that you are permitted to believe that by the evidence then that is enough. I am inclined to a somewhat stronger view to say that the evidence should make the premises more plausible than their negations. If the evidence makes the premises more plausible than their contradictories then the rational person should believe the premises rather than the contradictories. They don’t need to be certain. They don’t need to be highly plausible. They just need to be more plausible than their opposites. Some will say that is not sufficient for a good argument because perhaps each premise taken individually is more plausible than its negation but nevertheless when you consider the premises collectively maybe they are not more plausible than the negation of all of them. That could be the case but I think that you’ll find in the arguments that I present we will also meet that somewhat higher standard. For example, in the kalam cosmological argument that states:

1. Whatever begins to exist has a cause.

2. The universe began to exist.

3. Therefore the universe has a cause.

It seems to me that that first premise “Whatever begins to exist has a cause” is virtually certain so that the real crux of the argument will be the plausibility of the second premise – that the universe began to exist. The plausibility or the goodness or the cogency of the argument will not be reduced by any uncertainty attending the first premise which, to my mind, is rationally compelling.

Those are just some random thoughts upon natural theology and building a case for God’s existence.

On your outline, you will see arguments in support of God’s existence. They are listed – the ones we are going to discuss. This is just an overview not meant for you to take notes on. Rather, you have a separate outline for the first of these arguments or considerations which is the proper basicality of belief in God or belief in God as properly basic.

By way of introduction, this isn’t really an argument for God’s existence; rather it’s the claim that you can know that God exists wholly apart from arguments. This is still part of natural theology, I think, because what it is arguing is that belief in God can be rational and warranted apart from Scripture in accord with natural reason, but it doesn’t need to have argument.

The chief proponent of this point of view today is the great philosopher Alvin Plantinga, formerly of the University of Notre Dame now retired. He has a book that I highly recommend called Warranted Christian Belief. What Plantinga argues is that belief in God can be warranted (and is warranted) wholly apart from arguments. Plantinga makes clear in this book that he does think that when you consider the arguments for God’s existence it is more than probable that God exists. The probability based upon the arguments alone is that there is a God. But while he thinks the arguments are sufficient to justify and warrant belief in God they are not necessary. You can have warranted rational belief in God wholly apart from arguments. Plantinga calls this Reformed Epistemology, after the Reformer John Calvin.

Let’s look at this more specifically. I put it in the form of an argument even though this isn’t an argument for God’s existence.[4] It is an argument that belief in God can be warranted wholly apart from arguments. This is an argument for taking belief in God as properly basic.

1. Beliefs which are appropriately grounded may be rationally accepted as basic beliefs not grounded on argument.

Philosophers call beliefs which are rational to hold but not grounded on argument “properly basic beliefs.” They aren’t based on some other beliefs; rather they are part of the foundation of a person’s system of beliefs. Examples of properly basic beliefs would be things like the belief in the reality of the past (that the world wasn’t created five minutes ago with built-in appearances of age), belief in the existence of the external world around you, belief in the presence of other minds like your own. When you think about it, none of those beliefs can be proved on the basis of argument. How could you prove that the world was not created five minutes ago with built-in traces of age like breakfasts in our stomachs that we never really ate and memory traces in our brains of events we never really experienced? How could you prove that you are not a brain in a vat of chemicals wired up with electrodes by some mad scientist who is stimulating you to believe that you are here in this class listening to this lesson? In fact, he could be stimulating your brain to make you think it is absurd that you could be a brain in a vat of chemicals being stimulated by a mad scientist. How could you prove that other people really have an interior mental life like your own? That they are not just like the android Data who give all the external appearances of an individual with a mental life but in fact are just soulless robot-like automatons? There is no way to prove those sorts of beliefs. Rather, these are simply basic beliefs that we have that lie at the foundation of our system of beliefs.

Although these beliefs are basic for us (not founded on argument), that doesn’t mean that they’re arbitrary. Rather these sorts of beliefs are grounded in that they are formed in the context of having certain experiences. For example, in the experiential context of seeing and hearing and feeling things, I naturally form the belief that there is a world of physical objects around me that I am sensing. Thus, my basic beliefs are not arbitrary, but appropriately grounded in experience. There may be no way to prove such beliefs, but you are perfectly rational to hold them. In fact, you’d have to be crazy to think that the world was created five minutes ago or that you are a brain in a vat! These sorts of beliefs are not merely basic, but they are properly basic because of their grounding in experience.


Student: How would you defend a properly basic belief like the reality of the world to someone with a more Eastern mindset that might say the world is, in fact, an illusion or we are maybe, not brains in vat, but spirits experiencing an illusion of a world?

Dr. Craig: You are quite right. This is what the Buddhist or the Hindu thinks – that this world is Maya, or the realm of illusion. I think in response to that type of person, this is exactly how you should respond. You don’t try to argue for the reality of the external world. That is going to be futile because any evidence you appeal to will be from the external world. So what you say to the Buddhist or Hindu is that this is a properly basic belief (and we will talk about defeaters later) and in the absence of any defeater of this belief I am perfectly rational to go with my experience and accept my experience as veridical.[5] So the person who claims that you are the victim of this massive delusion has a tremendous burden of proof to provide some defeater of that belief. Buddhists and Hindus have tried to do that. They’ve tried to propound these puzzles called koans – like the sound of one hand clapping. When you think about these, these supposedly demonstrate the absurdity of reason and the world around us. But I think those could all be resolved. They are not convincing arguments. So we are perfectly rational in the face of the Buddhist or Hindu to accept our experience of the external world as veridical. We will say something more about defeaters later, but that does come in here. Don’t think that because a belief is properly basic that it is indubitable or indefeasible.

Student: With the Buddhist you could also ask the question how they know they exist. That is properly basic. That is totally subjective. Following on you could ask, do you have a schedule? Do you have a calendar? Do you have a watch?

Dr. Craig: What you are emphasizing is that you could also try to defeat his belief by showing incoherences in it, or the unlivability of it – the practical impossibility of living with it. So why adopt such a view in the absence of good arguments for it?

Student: Nobody would ever live their life with that. The evolutionist would never live their life with such improbabilities.

Dr. Craig: As Ravi Zacharias has often said, When I am in India, if I step into the street, it is either me or the bus. It is not both/and. Even the Hindu or the Buddhist lives by the law of contradiction and recognizes the reality of the external world.

Student: What if an atheist were to insist that atheism were properly basic, as I think Ayn Rand would if she were alive today?

Dr. Craig: Really? I would like to hear that. I’ve often wondered about that. I don’t know of any atheist that does say that because it is hard on atheism to think of what sort of experience would make belief in the non-existence of God properly basic. As we will see when I get to premise (2), the theist (and particularly the Christian) can say that belief in God is properly basic because of the witness of the Holy Spirit to his own spirit. So he has a mechanism for grounding belief in the existence of God. But I can’t see what the atheist could say. Maybe the atheist could say, Confronted with horrendous evils and suffering in the world, it is just properly basic that there is no God. But if that is what he says then Christian philosophers can offer defeaters of that by showing there is no incoherence in the belief of an all-powerful and all-loving God and the existence of horrendous evil. I think the project of claiming that atheism is properly basic is one that has very dim prospects because of the lack of any sort of mechanism for appropriately grounding it. Remember it needs to be properly basic – it needs to be appropriately grounded.


2. Belief that the biblical God exists is appropriately grounded.

This is the way that people in the Bible knew God, as professor John Hick (who was my doctoral mentor) explains:

God was known to them as a dynamic will interacting with their own wills, a sheer given reality, as inescapably to be reckoned with as destructive storm and life-giving sunshine . . . . They did not think of God as an inferred entity but as an experienced reality. To them God was not . . . An idea adopted by the mind, but an experiential reality which gave significance to their lives.[6]

What professor Hick is saying is that for biblical believers, God was an experienced reality, not the conclusion of a syllogism. I want to argue that, in fact, belief in God’s existence is appropriately grounded in the experience of God through the witness of the Holy Spirit.[7]

Rather than plunge into that at this time, we will end a bit early today but with the promissory note that the next time we are together we will look at the inner witness of the Holy Spirit, how that warrants belief in God (in the Christian God indeed) to the believer, and also I will argue to the unbeliever as well. Then we will talk about the question of defeaters of this belief and how it will relate to those. We will hold that until next time.[8]



[1] 5:00

[2] 10:07

[3] 15:07

[4] 20:00

[5] 25:00

[6] John Hick, “Introduction,” in The Existence of God, ed. with an Introduction by John Hick, Problems of Philosophy Series (New York: Macmillan Publishing Co., 1964), pp. 13-14.

[7] 30:13

[8] Total Running Time: 31:29 (Copyright © 2015 William Lane Craig)