Two Ways of Knowing

Before we get to today's episode, I would like to take a moment to invite you to join us next February for a Caribbean Study Cruise. You'll have the opportunity to meet me and other Renewing Your Mind listeners, and Ken Jones and Derek Thomas will be with us to teach through the rich theological truths of Galatians 3. Enjoy eight days of fellowship, teaching, and refreshment on Ligonier Ministries' 2025 Caribbean Study Cruise. If you'd like to join us February 22nd through March 1st, you can learn more and register at LigonierTours.com. I hope to see you then.

Now on to today's episode. The Bible records narrative after narrative after narrative that makes assertions about what people actually see or observe. That is, the resurrection of Jesus is not presented to us in the New Testament as a construction of fiction or as a theoretical abstract possibility, but the claim of the biblical writers is that there were an abundance of eyewitnesses who testified to seeing Jesus die and three days later seeing Him come back from the grave so that much of the testimony of the Scriptures rests upon empirical observation. The Bible speaks of our minds, and it speaks of our senses. It also assumes that our senses can be used and relied upon to observe the world around us.

As you just heard R.C. Sproul remind us, we're told in the New Testament about the eyewitnesses to the resurrection, or even Thomas, who wanted to see and touch the wounds of Jesus to believe. So how does reason relate to our senses?

What are the two ways of knowing? This is the Friday edition of Renewing Your Mind, and we've spent a week thinking about thinking and hearing messages from R.C. Sproul's series Think Like a Christian. Today is the final day you'll hear this series, so it's also the final day to request lifetime digital access to all 12 messages, plus receive Dr. Sproul's book, The Consequences of Ideas.

Simply give a gift of any amount at renewingyourmind.org or click the link in the podcast show notes. Well, for the final time this week, here's Dr. Sproul on two ways of knowing. As we continue now with our study of how the mind is to be engaged in the Christian life, we recall that we have looked briefly at the rigorous doubt process that was embarked upon by the French philosopher René Descartes in the 17th century, and we talked about how Descartes, after this doubt process, came to his fundamental axiom, I think, therefore I am. And we tried to see that the reason for this whole process was that Descartes was searching for certainty.

He wanted to find some basis whereby he could know something for sure, and a lot of what he was wrestling with was the question of the degree of certainty that is reached by fundamentally two different avenues of investigative pursuit. That is, on the one hand, what we call the deductive approach or the formal approach to truth, and then there is the inductive approach or what we would call the material approach or, as sometimes more technically called in philosophy, the empirical approach. Again, that word, which may not be familiar to everyone, empirical, has to do with that way in which we seek knowledge by the senses, by sight or by hearing or smelling, tasting, touching the five senses. Now, historically, the scientific method that we speak of and which we teach our children in even as early as elementary school is a method that has two legs on this particular stand, the deductive and the inductive or what we might call the formal and material or the rational and the empirical. Now, sometimes we have a tendency to think that the whole scientific enterprise is based purely on sense perception or on the knowledge that we gain through the senses, because the keen scientist is very much concerned about gathering data, studying behavioral patterns of various things in laboratories and so on, testing his theories with different experiments in order to validate or verify his theories empirically, that is, on the basis of observable or measurable data or evidence. Now, that is the inductive side of the scientific method. Now, what we mean by induction is that the process of induction moves from the particular to the universal or from data bits, if you will, to laws.

Now, in a very simple way, we do it this way. We observe and record our observations, particular incidents or examples of something. We may, for example, look at squirrels, and we may look at ten squirrels and see that all ten of them have bushy tails. Then we may expand our studies to a hundred squirrels, and we see that all hundred of them have bushy tails. And we may expand to a thousand or to a universe of a hundred thousand squirrels, and voila, we find a hundred thousand bushy tails. Well, pretty soon we begin to get enough data to make the assumption that bushy tail-ness is an integral part of squirrel-ness, so then we'll make a law that all squirrels have bushy tails. But, of course, we have a couple of problems with that. One problem we run into is the squirrel that got run over by a lawnmower and lost his bushy tail, or one that goes through some kind of genetic deficiency and is born without a bushy tail. But beyond those anomalies, as we call them, we also have the other problem of finite investigation. No person has ever had the opportunity to study every squirrel that is or has ever been. And so we can never have an exhaustive, comprehensive knowledge of all squirrels.

Yet science doesn't wait until we can examine every conceivable particular before we universalize. And this is what happens in the study of statistics and the taking of polls, where now all the drama of election night waiting for the returns that come in that I can remember from when I was a boy, where you'd stay up half the night listening to the radio as the results would be pouring in from the differing precincts, and you're wondering whether Truman was going to win the presidential election or Dewey. And you remember that incident, those of you that are old enough to remember, that when the newspapers went to bed that it was clear to them on the basis of their projections that Dewey was going to win, and I forget which major paper it was, had banner headlines for the morning edition. Was it the Chicago paper? I thought it was the Chicago paper, declaring that Dewey wins. Well, Dewey didn't win.

Truman won, and the Chicago paper had egg on its face as well as on its headline the following morning. Nowadays, when we watch these things, the sophistication of computer analysis of a very small percentage of reports that have come in after one or two percent of the vote has been tallied, now they're projecting the victor. And that is not done willy-nilly. That is done with the application of basic principles of statistical analysis and so on. And that kind of sophistication is what we've grown to expect from the scientific community. Well, that's all a process of induction.

Now, the benefit of induction to science is that it puts a break on wild speculation or theorizing where somebody can say, well, I believe personally in the existence of poltergeists or little men made out of green cheese who live on the other side of the moon. And we say, well, what evidence do you have for your poltergeist? Say, well, I saw one. Well, then we find 15 other people say that they had experience with poltergeists. They put it to the team of scientists. You study it, and you find out that the evidence begins to evaporate. Until then, the person says, well, my poltergeists have a peculiar quality to them. They're allergic to scientists and to all kind of scientific equipment. So they always disappear at the first sight of an incoming scientist.

Well, that kind of begging of the question is suspect indeed. But again, what we do, I mean, you could say that induction is the very heart and soul of modern scientific research. It is the gathering of the data.

It is the making of careful observations and measurements, even using sophisticated equipment like microscopes and telescopes and so on, and examining the particulars so that we can learn a lot about the particulars to come to looking for general rules or laws. Because one of the goals, one of the practical goals of modern science is to be able to predict results. And that's true for the application of particular medicines to different groups of people suffering different symptoms.

We know that every individual in the world is to some degree unique, and not everybody is going to respond in the same exact manner to a particular medicine. But doctors are making judgments on the basis of inductive research, and we would be in serious trouble if we did away with inductive research. Now, I've always complained, however, that the great weakness of modern science, particularly American science, is on the other leg of the stool, the deductive side.

The deductive side of the scientific method has to do with the conclusions you reach or the inferences that you make from the data that you collect and observe and do experiments with. For example, just the other day I got a letter from somebody who was complaining to me about a criticism I made about quantum physics. And I said, look, I have no problem with quantum physics, and if scientists tell me that the behavioral activity of subatomic particles is such that it's indeterminate, I'm not quarreling with that whatsoever. My quarrel is with how some physicists have articulated the results of those experiments by using language that is flatly contradictory. I said, my problem is not with the research.

My problem is with the conclusions that people are drawing or in the way in which they're articulating those conclusions by speaking in an irrational, absurd way. But in any case, deduction has to do with the rational treatment, if you will, of the so-called facts or of the data. Now, science is saying, therefore, with the scientific method that seeks to apply both the rules of deduction and principles of induction, that the scientist is saying that the whole enterprise of knowing is one that involves not only the senses but also the mind. And what we're calling the scientific method here I don't think is all that different from the way in which the Scriptures speak. As we noted in our last session, the Bible is constantly making references to things that happen in the external, perceivable world. As I mentioned, Peter said, we don't declare to you cunningly devised myths or fables that somebody could just simply weave out of their own speculative imagination, but we declare to you those things that we have seen with our eyes and heard with our ears. In other words, the Bible records narrative after narrative after narrative that makes assertions about what people actually see or observe.

That is, the resurrection of Jesus is not presented to us in the New Testament as a construction of fiction or as a theoretical abstract possibility, but the claim of the biblical writers is that there were an abundance of eyewitnesses who testified to seeing Jesus die and three days later seeing Him come back from the grave so that much of the testimony of the Scriptures rests upon empirical observation. But beyond that, we have to say if something is observed in nature or in the external, perceivable world, the obvious question that we're going to ask regarding that information that we get through the census, the obvious question is, so what? What is the significance of all of this?

What is the meaning of all of this? And that's where the mind is now actively engaged in trying to understand the import of the data that we are getting. And this is not just, as I said, an exercise in speculation. Now again, we see that the scientific method, to be scientific in the full measure of it, includes both of these elements, and on the surface it looked as if Descartes was eliminating half of it, namely the inductive side, because he was going to doubt every single thing that he could doubt in terms of what was perceived. He said, I never can know for sure that my senses are not deceiving me. Now that's one problem that we looked at the other day in terms of the subject-object problem. The other problem is that we never can have absolute certainty about anything from the census.

Let me say it again. We never can have absolute certainty about anything simply from our senses. And somebody might look at me and say, are you crazy? Are you saying that I cannot have absolute certainty about the truth of something that I see with my own eyes?

Don't we have the axiom in our culture, seeing is believing? And if I were standing there in front of that tomb on Easter morning and saw Jesus come out of that grave and in His resurrected state, wouldn't I be absolutely convinced of His resurrection? Well, I'm sure that you would be, and I'm sure that I would be, because we put a lot of weight on what we can see with our own eyes or hear with our own ears, because over the years of our personal experience, we have come to the place where we invest a lot of credibility in our own particular experience, that is, not just what we're feeling, but what we're actually observing or actually hearing with our own ears. Now, when I said that this kind of knowledge never gives you absolute certainty, maybe I tricked you a little bit. You might be able to say, I might say, did you see what you saw? And you'll say, yes. I said, are you sure?

And you say, yes. I said, are you sure you're sure? And you'll say, I'm absolutely certain.

I say, well, OK. You may have an emotional state of assurance that to your mind cannot possibly be improved, that it is absolute in that sense. But when we talk about absolute certainty, I'm using that term in the philosophical sense. Absolute certainty refers to that which cannot really rationally be questioned.

But we know, as Descartes was getting at, that eyewitnesses can be wrong and that not all eyewitness testimony is infallible, that people think they see things that aren't really there. Now, what we call probability quotient of a massive eyewitness testimony may be astronomical. If 100,000 people agree completely on seeing a given event on a particular day, it's extremely unlikely that all 100,000 of them were undergoing an illusion or a hallucination. But theoretically, is it possible that 100,000 people at the same time have a hallucination? Yes, it's possible.

It's extremely unlikely. You run into this problem of evidence in the courtroom, particularly when we talk about reasonable doubt. It is the burden in criminal cases of the prosecution to prove their case beyond a reasonable doubt. That's not the same thing as beyond a shadow of a doubt. You can raise doubts about anything if you want to, except that you are doubting, because the doubt that you are doubting proves that you are doubting. But this is what Descartes was trying to get at.

He's saying there are built-in limitations to the empirical side of knowledge. We never can have absolute certainty from our senses. Well, is there anywhere we can have absolute certainty? Well, Descartes said yes. In the formal realm, in the deductive realm, in the rational realm, we can have absolute, rational certainty. And that takes us to the standard syllogism.

And let's look at the one we've all studied when we were children. All men are mortal. Socrates is a man. Therefore, what?

Socrates is mortal. Now, let's look at these premises. The first premise, all men are mortal. Can we know that absolutely?

No, because we haven't examined all men, have we? It may be that every human being that ever lived prior to this moment was mortal. But this generation of people is the first generation in history that is immortal.

Now, that's highly unlikely, and we don't know it. And we may find out that all of us are going to die demonstrating our mortality. And then suppose you're the only person left alive in the world. Now can you be sure that all men are mortal?

No, you may be, extraordinarily as it would be, the lone example. The only way you can know with absolute philosophical certainty that all men are mortal is posthumously. That is, if everybody dies. All right, all men are mortal. But we assume on the basis of the data and an astronomical probability quotient that all men are mortal. Do we know that Socrates is a man? Maybe Socrates was a fig newton of Plato's imagination. Maybe Socrates was an alien from another planet.

Those are wild, crazy possibilities. But I'm just saying we don't know for certainty that Socrates is a man. But here's the value of the syllogism. If all men are mortal, if this premise is true, and if Socrates is a man, if that premise is true, then we know with absolute certainty that Socrates was a man.

That is, here the deductive side, the formal side, gives us the certainty of an absolute conclusion that is proven demonstratively from the premises. Now, that becomes crucial for not only natural science, but also for theological science, as we will see in the days to come. My purpose today is not to create skepticism in your mind about what you see and what you hear and what you experience.

That's not the purpose at all. I believe, for example, and assume that the senses that I use to observe and to hear what's going on around me, though they are not perfect and though they are not infallible, nevertheless are reliable, and that I believe I'm morally responsible to act according to the perceptions that I have and that we convict people and execute people on the basis of external evidence such as that sort. And so what we don't want to do here is leave us in a sea of cynical skepticism about science or about sense perception. This is how we are constructed as creatures. As I said, my only transition, my only portal from my mind to the world outside of my mind is through my senses. And so I put great weight on sense perception, as the Bible did, and as science does. I'm only saying, remember there are limits to these things.

That was R.C. Sproul, the founder of Ligonier Ministries, on this Friday edition of Renewing Your Mind. Dr. Sproul had a vision to flood the world with knowledgeable and articulate Christians.

That's why he taught not just on theology but philosophy, biblical studies, church history and other areas to help God's people grow in their knowledge of God's Word and the world in which we live. And when you support Renewing Your Mind, you're helping advance that vision. So to thank you for your donation of any amount today at renewingyourmind.org or when you call us at 800 435 4343, we'll not only grant you lifetime access to this 12-message series, Think Like a Christian, but we'll also send you his book, The Consequences of Ideas. Learn how the ideas of philosophy have shaped the world we live in today and be warned as you see some of those ideas, destructive ideas, return to modern thinking today. Click the link in the podcast show notes or give your gift when you click today's resource offer at renewingyourmind.org. But be quick because this offer ends at midnight. What we often refer to as the doctrines of grace were not an invention of the 16th century, but instead these truths are found throughout the Bible. And beginning Monday, Stephen Lawson will start a survey of the New Testament to show us that salvation truly is a sovereign and gracious gift of God. Be sure to join us then here on Renewing Your Mind. .