Christian Apologetics - Lesson 9


Discussion of deductive presuppositionalism vs. inductive presuppositionalism.

Ronald Nash
Christian Apologetics
Lesson 9
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Worldview Issues

Part 2

VI.  Methodology

A.  Deductive Presuppositionalism

1.  Gordon Clark

2.  Gary North

3.  Differences between Clark and Van Til

B.  Inductive Presuppositionalism

1.  Abductive

2.  The Mixed Hypothetical Syllogism

a.  Valid Forms

b.  Fallacious Forms

3.  Other Examples

a.  Scientific investigation

b.  Investigating a crime

c.  Explaining a historical event

d.  Interpreting a text

4.  Reasoning to the best explanation

  • Introduction to Apologetics.

  • Apologetics involves finding evidence and presenting arguments to defend the Christian faith.

  • Two prominent worldviews are Christian theism and naturalism.

  • The law of non-contradiction states that A cannot be B and non-B at the same time and in the same sense.

  • Explanations and responses to different worldviews.

  • If God is good and all powerful, then why does evil exist?

  • Discussion about how the existence of evil is consistent with God's character.

  • Your noetic structure, presuppositions and view of epistemology are important elements in the formation of your worldview.

  • Discussion of deductive presuppositionalism vs. inductive presuppositionalism.

  • Objections to inductive presuppositionalism.

  • Arguments for and against evidentialism.

  • Arguments for and against foundationalism.

  • Discussion of natural theology.

  • There are valid, sound and cogent arguments for the existence of God, but no coercive proofs.

  • Discussion of different arguments for God's existence.

  • One version of the cosmological argument for God's existence emphasizes God as first in time, another emphasizes God as first in importance.

  • A possible world is a way the real world could have been. Modal logic, propositions, state of affairs and eternal entities are some of the considerations when discussing a possible world.

  • Something is logically possible if its description does not include a logical contradiction. The existence of the laws of knowledge refute the system of naturalism.

  • Middle knowledge is a form of knowledge attributed to God by Molina.

  • Miracles are a dividing line and central to Christianity.

  • David Hume's rational arguments against miracles and responses to those arguments.

  • Two miracles central to Christianity are the incarnation and resurrection.

  • The question of whether or not Jesus is the only savior touches on pluralism, inclusivism and exclusivism.

  • Pluralism is the view that all religions have salvific value.

  • Salvation is totally the work of God and all children who die in infancy are elect of God.

  • Inclusivism is the view that even though the work of Christ is the only means of salvation, it does not follow that explicit knowledge of Christ is necessary in order for a person to be saved.

  • Discussion from a biblical perspective of God's character and attributes.

  • Open theists believe that God does not have a perfect knowledge of the future.

  • Divine omnipotence and divine omniscience are two attributes of God.

  • When contemplating life after death, remember, Jesus has been there and come back. Will you commit your life to him or reject him?

These lectures were given at Reformed Theological Seminary in Orlando, Florida during the fall of 2001.


Dr. Ronald Nash

Christian Apologetics



Lesson Transcript


[00:00:01] Now I want to turn finally. To page 59, and I want to talk about methodology. There are three kinds of presupposition. So the first thing we're going to do is we're going to notice that there's a difference between deductive presupposition wisdom. And of course, then the other kind of presupposition wisdom would be inductive presupposition wisdom. But even though that's the word I use in your textbook, there really is a more accurate word, a better word, but I don't use it in the textbook because it would intimidate a lot of people. All right. The better word is abducted, But I use inductive to just sort of bring stuff down to a little easier level. Now, there are then two, two forms of deductive presupposition, holism. And this is what blows the minds of a lot of people. One of these people is Cornelius Van Tille, and the other one is Gordon H. Clark. Now, a lot of people around here think that I'm a kind of mind numbed robot of Gordon age Clark. But what you're about to see in the next 5 minutes is I'm going to I'm going to start a fight with Gordon Clark. I'm going to disagree with him. And I'm going to blow a lot of people's minds because I think there isn't a whole lot of difference between Gordon Clark and Cornelius Van Till. Now, why will that blow some people's minds? Because these two guys fought a heresy fight within the early years of the Orthodox Presbyterian Church. Cornelius Van Tille and his groupies of the time accused Gordon Clarke of heresy. And they had a big trial in the church. But the truth is, these guys weren't that far apart. Now, what do I mean by deductive presupposition wisdom? Well, let me explain it first in terms of Gordon Clarke. Gordon Clarke believed this at the end of his life. In his later years, Clark treated the Christian faith as a kind of geometric system, as a kind of axiomatic system. And the basic or the fundamental postulate of his axiomatic system is the Bible is the word of God. That's just basic presupposition. Gordon Clarke believed that there were only two kinds of knowledge that human beings could attain. Listen to this. One kind of knowledge we can obtain is knowledge of the actual propositions that God has revealed in Scripture. Now. I'll agree with that. David was king of Israel. In the beginning, God created the heavens on the earth and the word became flesh and dwelt amongst us. And we beheld his glory as of the only begotten of the Father, full of grace and truth. I agree that those propositions in Scripture are items of knowledge. And the only other thing we can know then are truths that we deduce from the propositions of Scripture. That's all we can know. Now, I don't quarrel with what Clarke says there, except I believe we can know a great deal more. This is a true story. I don't know whether I've told it here or not to you. I was once speaking at the at what? At that time was the National Seminary of the Campus Crusade for Christ. And so I gave some lectures there. This would have been 20 years ago or so. And afterwards, one of the professors invited me into his office. And he had a big office, probably 4 to 5 times as big as my office here. Bigger than anybody's office here, for that matter, anyhow. It was full, full of books. I said to this guy at the Campus Crusade Seminary, I was trying to make small talk. I said, What's your favorite book in your whole library? And then I realized that he was going to answer that question. He got up from his chair behind his desk. He walked all across this room. It took him about 5 minutes to get to the other side. All right. And he picked up two heavy books. I was afraid he's going to get a hernia. And he carries these two heavy books over to the desk in front of me, and he drops them on the table. I said, What's in these two books? He said, and I'm making my point here. He said in these two books. They must have been 18 inches high in these two books. Two little old ladies in San Francisco deduced the entire system of arithmetic from the Bible. And I blurted out, Why would anybody be so dumb as to do that? All right. What these ladies did was they went through the Bible and they found passages from which they deduced one plus one equals two and gave the chapter in the verse. One plus two equals three and gave the chapter in the book. I don't know how they did that. That is deductive presupposition, Ellis. Now, in that case, I guarantee it wasn't Gordon Clarke's deductive presupposition wisdom. It was Van Tulleken ism. What I'm trying to show you with my story is how a deductive presupposition which thinks, okay, but because on this particular point, there is little, if any, difference between Gordon Clarke in his later years and many of Van Tils disciples, not necessarily those presently on our faculty, but people like Greg Bronson, Garry North, the whole group of the economists. Yeah, you mouthed the words too. This is a group that's really splitting up the church. Take economics, for example. Garry North is the son in law of a recently deceased Van Tillie and named Rousseau's Rushdoony. Rousseau's Rushdoony is the guy I mentioned a couple of weeks ago who wrote a book in which he said that Nash worships the law of non contradiction. He has an eye, he has an alter to the law of non contradiction in his backyard. Now Gary North and Russell's Rushdoony, even though one was the father in law and the other one was the son in law. They didn't talk for a long number of years. They didn't have a very good relationship. But Gary North holds to a system of economics that is almost identical with mine. In case you care. All right. But there's a big difference. Gary North says this about my economics, and it's published in the book Poverty and Wealth. Great book. Great book. Gary North says the difference between Nash's economics and mine is this Nash gets his economics from a dead white European male named Ludwig von Mises. But I, Gary North, get my economics from the Bible. He deduces his economics from the blind. Does he does is it he's got you know among his publications is a long economic commentary derive from the Pentateuch. The animals believe that the Pentateuch gives us God's blueprint for society. And so what we do is we take these propositions and Scripture and then we deduce what we're supposed to do with them. Okay, Van tells basic presupposition is the Bible is the word of God. And then we, at least according to the methodology of some of his followers, you then deduce what you know about everything from Scripture. I wouldn't suggest that that was true to Van Till, but you can't deny that that's the way most of these guys operate. Okay. But here are the differences there. Methodology is the same. Okay, that's my point. The methodology is the same, but there are important differences. And here would be some of the important differences. Gordon Clark believes that the laws of logic. Are necessary and essential laws, without which sound theology and sound philosophy are impossible. On the other hand, van till taught or so I think you got to understand there. There are a lot of ambiguities in Van til, but Van Till taught that God created the laws of logic. Now, I know that's a controversial statement. And I don't know whether John Frame would agree with that, but I do know that a lot of ventilations, I do think that's what they until now. So because the law if if if you're a Van Tilley and you believe that he thought that God created the laws of arithmetic, the multiplication tables and the laws of logic, then the laws of logic are not necessarily truths, they're optional. And, you know, look, when I'm trying to start any argument or disagreement. I think you all know that there are Van Chileans who don't get particularly excited about the need to defend the law of non contradiction. I mean, I I'm basically the only guy who spends a whole lot of time doing that. Okay. So that was an important difference between Clark and Van Hill. Another important difference that is related to that is this, that human beings can know the nature of God through general revelation. That's. That's Clark. Human beings can attain knowledge of God's nature through general revelation. Now, I got to admit right here, that seems to be that seems to contradict some of the things I said about Gordon Clarke earlier. And I'll leave it for you to resolve that in a paper. Okay. I'm not it's not my duty here to defend Gordon Clarke here or to eliminate any possible inconsistencies. But, Van, to argued for the incomprehensibility of God that we really can't know. And and correct me if I'm mistaken here, I don't think even on the basis of scripture, we can we can we can know God's nature as it really is proven to. Okay. Now, it was differences like that that led to the heresy trial between Van Tille and Clarke. It wasn't the methodology. It was other presuppositions about logic, the relationship between God and logic, our accessibility to information about the nature of God and so on. Okay. Now I hear I'm on the side of Clark that we can when we know truth, we know something about the nature of God. Only I would go beyond Clark and say we can know something about the nature of God, whether you can find some kind of scriptural support for that or not. Some things are true. Ladies and gentlemen, get this in your notes and give me credit for this. Some things are true not because they're taught in the Bible. Some things are true just because they're true. Period. All right. And if that's a revolutionary idea, then may I get credit for it? Okay. Nothing revolutionary about it at all. I have on a few occasions imagined Clark and Van Chill bumping into each other in heaven for the first time. And I don't know who would initiate it, because they were both very stubborn man. Believe me, you know, you got a Dutchman, and I mean, you got to Presbyterians here. They're both stubborn guys, all right? Neither one is a Baptist. You know where the milk of honey flows and all human relationships. And I can. I can imagine Clark and Van chill embracing each other and sort of laughing and saying, weren't all of those arguments kind of foolish now? And they agree that those arguments are kind of foolish now. And then Clark says, But of course, as you know, I was right. Ha ha ha ha ha. Okay, well, that's enough for deductive presupposition, Elizabeth. I think it's what I have described my approach, my methodology, as inductive presupposition wisdom. Carl Meisner, incidentally, bless his heart, he recognizes that there are more kinds of presupposition holism than the kind represented by Cornelius Van Tille and his followers and Cal Blaser, whose views have changed a little bit over the years. He now says to me he comes closest in his current position to what he calls classical presupposition, a lesson which he relates to Gordon Clark and Carl F.h. Henry and others. And I, I wrote Cal and I told him he'd better he'd better check out my distinction between deductive and inductive presupposition realism, because I think there even though I like this name, classic presupposition wisdom, my position has changed considerably from my earlier own earlier adventures with Gordon Clark. Okay, so we call I called my view inductive presupposition wisdom, and I used the word inductive when I wrote the book because the more accurate term would would intimidate some people, would confuse people because it is not a word that very many people can define. But let me just explain what the word abducted or abduction refers to. Okay. If you've ever studied traditional logic, that is the kind of logic that was current 30 years ago or so before symbolic logic became so, so popular. One of the standard ingredients of a of a more traditional and older kind of logic course studies what is called the mixed hypothetical syllogism. I am not being cute here. This is really quite important stuff. Now, the mixed a mixed hypothetical syllogism has two premises and a conclusion. One of the premises. Get all of this in your notes. One of the premises of a mixed hypothetical syllogism is what we call a hypothetical statement. And a hypothetical statement is a statement that assumes the form. If. If. Then. Okay. So here's one example of a mixed hypothetical syllogism, and this will be a valid form of a mixed hypothetical syllogism. If a where a is some proposition, then be okay. That's that's that's the major premise. And in fact, the major premise of all of the forms of a mixed hypothetical syllogism will be forms that resemble this. Okay. Then the second premise of a mixed hypothetical syllogism is what we call a categorical proposition. I'll give you an example in a moment. And then the conclusion is going to be a categorical proposition. To say that it's a categorical proposition simply means that there's nothing hypothetical about it. It's simply a bold statement. I love bold statements. Okay. Now, here's an example, and I don't want to write this on the board. If Ron Nash has won the Masters Golf tournament, you can tell how hypothetical this is. Okay. I should have worn my green jacket today. If Ron Nash has won the Masters Golf Tournament, then Ron Nash has played at least 18 holes of golf at the Augusta National course. Okay. Now, suppose that be the antecedent. That is the first part of our hypothetical statement. Assume that's true. Ron Nash has won the Masters Golf tournament. Then it is also true. The consequence. We call this the antecedent. We call this the consequent. Then Nash has played at least 18 holes on the Masters Golf tournament. Now, whatever you think of the truth of the premises, this would be a valid argument that illustrates the next hypothetical syllogism. Let's call this form one. Okay. Now, the only other version of the mixed hypothetical syllogism that can be valid, let's call it form two. It would go like this. If A then B, if Nash has won the Masters Golf tournament, then he has played at least 18 holes on the Augusta National course. Not B, that is B is false. Therefore, not A NASH has not played 18 holes. See there's discrimination at the at the Augusta National course. They won't let anybody play who's a lousy golfer. And that's why I haven't played 18 holes there. Therefore, I have not won the the the the Masters golf tournament. So the two valid versions of the mixed hypothetical syllogism either require you to affirm the antecedent or to deny the consequent. If you affirm the antecedent, then you must affirm the consequent. If you deny the consequent, then you must deny the antecedent. Those are the only valid versions of the mixed hypothetical syllogism. Now, there are two fallacious forms, and let's call this form three. If a then B B, therefore A, this is always invalid. Consider our example. If Nash has won the Masters Golf tournament, then he has played at least 18 holes on the Augusta National course. Nash has played 18 holes on the Augusta National course. That's B. Therefore, Nash has won the Masters. Well, you can see how that's invalid. The world contains a large number of people who have played 18 holes. On the Augusta National course brought up there. Only a very few of those people have actually won the golf tournament. So just because you played the course doesn't mean you've won this prestigious golf tournament. You see the fallacy. Now, the other form and we have a name for this fallacy. We call this the fallacy of affirming the consequent. I'm not going to ask you that stuff. You can get it in chapter eight of the Faith and Reason book. I'm not going to ask you this. I just want to help you understand what abduction is. Then form four would be if A then B, not A, therefore not B. Now, this fallacy also has a name. It's called the fallacy of of of denying the consequent. If Nash's if Nash has won the Masters golf term, then he's played 18 holes. He has not won the Masters. Therefore, he has not played 18 holes. Well, clearly that doesn't follow. Just because I haven't won the Masters golf tournament, it doesn't follow that I haven't played 18 holes of golf there. Now, here is the point that I want you to understand. This is technically, logically a fallacious form of reasoning, but it nonetheless is a model of the kind of reasoning that is utilized in at least four disciplines of human thinking. And those four disciplines are scientific experimentation, historical understanding, explaining a text, explaining the meaning of a text, and finally solving, you know, solving a crime such as you find in a detective novel, solving a crime. It is also the methodology that I use in this apologetics course and in that apologetics book. This is a this this is a situation that described that that some people that strikes many people as strange, that a form of reasoning that is deductively invalid can nonetheless function as a as a as a reasonable and credible method of reasoning. And this is what we call abduction. Now, let me quickly give you these examples, and I'm going to give them to you out of order. Let's take a scientific experiment. Here's the hypothetical statement. If litmus paper is immersed in acid, it will turn blue. Do I still have that right? I only talk about litmus paper every two years. Did I get that right? You scientists here. Okay. If a then B, the litmus paper turns blue, therefore, the liquid is acid. Okay. Now you can consider any number of other laboratory experiments where the experiment is set up in a way like that. I had a blood test taken a couple of days ago. I have diabetes. One of my standard tests is called the A-1 C test, which shows a number. That indicates my average blood glucose level for the last three months. Apparently blood cells have a way of of retaining a certain amount of blood of blood glucose. And if you're diabetic, you always want that H1 C number to be seven or below. Okay. Which is what my number was a year ago. I am rather confident that when I get the number in another week, it's going to be over eight. And there's no way to hide this. My doctor is going to look at that number. It may be eight, it may be 8.5. And he's going to know that I have sinned. Okay? I have sinned. There's no way to escape it, ladies and gentlemen. You see, I used to play games with my endocrinologist. I would starve myself for the week before I take this test, and then I. And then I'd get a one shot one day blood sugar level. That would be maybe one 3125 something. And my endocrinologist back then would say, okay, you're doing all right. See, But this shows that I've been cheating for three months. Now, the scary thing is this endocrinologist may be from Afghanistan and he may do terrible things to me. I don't know. We're going to find out. So there again, or else what I can do is I can say, Doctor, you've looked at that number and you have committed the fallacy of affirming the consequent. And he'll look at me and say, You jerk, I don't know what you're talking about, but you still cheated on what you ate. All right, here's another example. Let's take one of Agatha Christie's novels. All right. Say it's Hercule Poirot, and we have a crime. Somebody has been murdered. Maybe the body has been found down on the beach, and we begin to look for evidence. Now, of course, if you've read Agatha Christie's books, you know that her the first set of clues are always what we call red herrings. In other words, by the time you get to the middle of the book, you're going to be convinced that somebody else did the crime. But then something some new piece of information will arise and you will know. Well, for example, by the middle of the book, you may decide that Colonel Mustard did it in the kitchen with a knife. You Americans will appreciate that. That's a board game. We call it Clue. Okay. But then by the middle of the book, you'll discover that Colonel Mustard could not have done it in the kitchen with a knife, because perhaps by that time, Colonel Mustard will be the second victim of this horrible killer. And then you may think that Miss Scarlett did in the basement with a, you know, a wrench or something else. But then by the end of the book, you'll discover that the butler did it. Butler always does. Butler did it. That is abduction. No one questions the legitimacy of that kind of reasoning. Third example explaining a historical event. And in the textbook, I use the decree adopted by Queen Elizabeth, the first of England, when she was crowned as Queen of England. It was the practice in those days to to pronounce a a statement of all of your rights and privileges. And I quoted in the book, Let me find it here. I'll get to it in just a moment. Here's the statement. This is on page 62 of your book. When Elizabeth, the first became Queen of England in 1558, her official title read as follows. Quote, Elizabeth by the grace of God, Queen of England, France and Spain, defender of the faith, etc.. The end of the title. For decades, historians scratch their heads and said, What is that, etc. doing in the title of Queen Elizabeth? The first. She was the first and the last ruler of England ever to slip an etc. into her official title. Well, actually, when you finally get the explanation, it's not all that profound. It makes a lot of sense that etc.. In Queen Elizabeth's title, here is a historian trying to explain this. He's coming up with a hypothesis. The hypothesis might be something like this. If Queen Elizabeth. Wanted to temporize, that is, wanted to hide all of her true intentions. In 1558, she chose to do that by not enumerating all of her plans, but by simply covering them up, hiding them underneath that word, etc.. Well, of course, that's what Queen Elizabeth did. She didn't want the King of Spain to know that she had plans to make herself head of the English church. She didn't want the King of Spain to know that she she was definitely going to move England in a Protestant direction. All of that had to be kept quiet. Otherwise, Spain would have attacked England before it was ready to defend itself. So if a. Then B. B, therefore A. And then finally, the interpretation of a text. You have a you have an. Well, that would also apply to the text of Elizabeth's title. So we have another name then for this we call it reasoning to a best explanation. If this hypothesis, if this presupposition explains better than any other presupposition, this particular data, then that casts reliability and credibility back upon the presupposition. Okay. Well, that's basically the form that my presupposition wisdom takes. Life presents us with a lot of questions, problems, puzzles. Bring your presuppositions to the bar, I say, and I'll bring mine. And my presupposition is the basic assumption of the Christian worldview, that so-called touchstone proposition. And I will argue that the Christian worldview, with all of the content that we can derive from Scripture that gives form and substance to that Christian worldview will answer more questions and will leave fewer questions unanswered than any worldview hypothesis that you present. Okay, I can explain. Scores and scores of things that other worldview presuppositions cannot explain that casts credibility back upon the Christian worldview and then upon the sacred scriptures from which that worldview is inferred. So this is reasoning to the best explanation, and it ought to give you some comfort to know that the methodology of at least one apologetics system out there matches a kind of thinking that has respect in the world of scholarship. That's not why I adopted. But I think recognizing that can help eliminate some of the suspicion and initial bias against. My approach to apologetics. I can say to somebody, look, I'm using the same basic approach in my apologetics that you accept every day when a scientist does his work, that you accept every day when a historian does his work. When Hercule Poirot does his work and so on. Okay. So that's what I mean by inductive presupposition. Elizabeth, I'll let you read that material in the text and get from it what you can.