Friday, September 30, 2005

What is faith? part 2

But there is further reason I have for taking issue with the common understanding of faith as belief without evidence. I don't think the Bible advocates blind faith at all, but rather, it encourages critical thinking. First of all, 1 Peter 3:15 says, "be ready always to give an answer to every man that asketh you a reason for the hope that is in you with meekness and fear." In this passage, we are admonished to "give a reason" for the hope we have. Before we can give a reason for why we have hope, we have to first HAVE a reason for our hope. So this passage presupposes that our faith not be blind or arbitrary. It must be based on reasons. 1 Peter 3:15 is where the ministry of apologetics comes from. The Greek word translated as "answer" here and as "defense" in the NASB is "apologia," from which we get "apologetics," which involves giving reasons for thinking Christianity is true and answering objections to the Christian worldview. It's something that according to 1 Peter every Christian should do, but that requires them to engage the gospel on an intellectual level and not to be content with mere blind belief without reasons.

Part 3

Thursday, September 29, 2005

What is faith? part 1

A couple of years ago in one of my philosophy classes, the issue of "faith" came up, and predictably, just about everybody understood faith to mean "belief in the absense of evidence," or something like that. One guy in there was a Baptist pastor named Billy, he said, and he was especially adamant about this definition. He seemed to think it was downright inappropriate to make arguments for the existence of God, because it destroyed faith.

In our class email discussions, Billy and I debated the issue. It was a short debate. I basically wrote an email spelling out all my reasons for disagreeing with him, and he basically never gave much of a response. In the next few blogs, I'm going to be posting that email. Of course I'm cutting out big chunks of it that I don't think are all that important. Here we go...

***************
Billy: Belief in God focuses on faith. Faith is the substance of things hoped for and the evidence of thing not seen. (Hebrew 11:1)

Sam: Okay, this is where I'm going to get theological, and since you're a pastor, you may have better insight into these things than I do, but I want to tell you my point of view and see what you think of it. It seems to be your understanding that "faith" is "belief in the absense of evidence." After thinking about this for a while, I went to a Bible study Monday night and asked the people there to define "faith" in their own words. I wanted to see how many people would say the same thing, and there were a few who basically agreed that faith is belief in the absense of evidence. The same sort of thing came up in our philosophy class when we were pitting faith against reason, and a few people had the same idea of faith. I mentioned in another post that I disagreed with that understanding of faith, so now I want to say why that is.

I guess Hebrews 11:1 is a good place to start. It says two things about faith. First, it says faith is the substance of things hoped for. Second, it says faith is the evidence of things not seen. I suppose it is because of the phrase, "things not seen," that faith is taken to be belief without evidence. But that seems inconsistent with the fact that it says faith is the EVIDENCE of things not seen. If we take "things not seen" as the object of faith, then this passage seems to be saying that although we don't see the object of our faith, our belief in it is nevertheless based on evidence. I don't see anything unusual about this because there are many things we don't see but yet believe in because we infer it from evidence. For example, we believe in electrons, but nobody has ever seen an electron. We infer the existence of electrons based on what we DO see, so in the case of electrons, we have evidence for something that is not seen. Why couldn't belief in God be infered in the same way?

According to Hebrews 11:1, faith involves more than mere belief. It also involves hope. So not only do we believe in the "thing not seen," but we also place our hope and trust in it. The reason I define faith as "trust in what we think is true," is because by definition, to believe something is to think it is true, and because believing, by itself, isn't what faith is, but rather, faith is also hope and trust in the object of our faith. It's possible for me to have some belief but not put my trust in it. For example, I may believe that my chair is able to hold me up without ever sitting in it, but to sit in the chair is to trust it to hold me up. In the same way, a person may believe the gospel is true, but to have faith in the gospel is to actually trust in Jesus for their salvation.

I actually don't take the phrase, "things not seen," to mean things like angels, spirits, and things that we have no visual perception of. I take it to be referring to the substance of the things hoped for. The reason I take it that way is because this passage seems to closely correspond to Romans 8:18-25 where Paul is talking about the renewal of the cosmos and the resurrection, which he calls the "redemption of our body." He says, "For in hope we have been saved, but hope that is seen is not hope; for why does one also hope for what he sees? But if we hope for what we do not see, with perseverance we wait eagerly for it." What Paul means by "seen" here clearly isn't visual perception. He's just referring to an event that hasn't happened yet. In the same way, I don't take Hebrews 11:1 to mean "belief in something you can't see," but rather, "hope in something that hasn't happened yet." See how the two phrases, "substance of things hoped for," and "evidence of things not seen," go together according to this undersanding? Our hope is in a resurrection to eternal life which hasn't happened yet, and we place our faith in Jesus for that hope. It has nothing to do with belief in the absense of evidence.

Part 2

Wednesday, September 28, 2005

When arguments go awry

It's interesting when you do a lot of debating on message boards and stuff that there are some things you say that are guaranteed to be misunderstood. It's like something happens between the time the words leave your mind and arrive at the other person's mind. They hear something completely different than what you say. Here are a few examples:

When arguing for the resurrection, we will sometimes make the point that since the disciples were willing to lay down their lives for their beliefs, it's clear that they were not just pulling off some kind of scam; they really believed what they were saying. When you make this point, people hear something completely different. What they hear is that since the disciples were willing to die for their beliefs, then Christianity must be true. And then they'll point out the many other people from other religions who have been willing to die for their beliefs. I always respond the same way. I point out that the fact that other people are willing to die for their beliefs proves the same thing in their case as it does in mine. If people die for their beliefs, it proves they really believe it.

When spelling out the kalam cosmological argument, the first premise is "Whatever begins to exist has a cause to its existence." But that's not what people hear. What they hear is, "Whatever exists has a cause to its existence," and then they say, "Who created God?" They figure since God exists, then God must have a cause for his existence, too. Then you have to explain how there are two kinds of things in existence--those which had a beginning, and those which didn't. Those that didn't have a beginning don't require a cause. Those that do have a beginning do require a cause.

When making the moral argument for God, the first premise is that "If there is no God, then there are no objective moral values." But that's not what people hear. What they hear is, "If you don't believe in God, then you can't be moral." And then they go on to point out that atheists are often more moral than Christians, and they think they've refuted your argument.

Here's one more involving same sex marriage. Some people will defend same sex marriage on the basis that anybody ought to be allowed to marry if they love each other. To rebut that argument, we will point out that a brother and sister might love each other, so by their reasoning, we have to allow incest. Or we might point out that Jim, Jill, Jason, Joanna, John, and Jasmine all love each other, so by their reasoning, we'd have to allow polygamy, too. These are ad absurdum arguments. That's where you show that a position is false by taking it to its logical conclusion. The logical conclusion to the premise that people ought to be allowed to marry if they love each other is that brothers and sisters ought to be allowed to marry each other, and multiple partners ought to be allowed to marry each other. If we reject these conclusions, then we have to reject the premise they are based on since that premise leads inevitably to them.

But that's not what people hear. It's especially not what gay people hear. What people usually hear is this: If you start allowing gay marriages, then next thing you know, there'll be incest and polygamy. Then they'll accuse you of committing the slippery slope fallacy. (Of course in a sense, it is a logical slippery slope, but it's not the causal slippery slope they're accusing you of.)

Gay people hear something even worse. What they hear is that you're comparing homosexuality to polygamy and incest, and then they get offended. At this point it becomes impossible to reason with them, because they're offended. They refuse to actually address your argument from here on out, and instead whine about you likening their lifestyle to polygamy and incest because you're such a mean homophobe, and fundie, too. Of course the only sense in which you're likening them to incest and polygamy is in the fact that they love each other, but even heterosexuals love each other!

I tell ya, it's frustrating. The frustrating thing about it is that you know ahead of time that the person is going to hear something completely different than what you say, and you know ahead of time that you're going to have to correct their misunderstanding.

These are just a few examples off the top of my head. There are others. If you've noticed the same thing, please tells us about your experiences in the comments.

Tuesday, September 27, 2005

more on self-refutation

While I’ve got your attention, I want to talk some more about self-refuting claims. There are several claims that have been made in class that are self-refuting.

There are no absolutes: That claim is self-refuting because if there are no absolutes, then the claim itself is not absolute, and if the claim itself is not absolute, then there are at least some absolutes. If the claim is absolute, then there is at least one absolute, namely, the claim itself.

There is nothing that is not in a constant state of change: Is the truth that nothing changes an unchanging truth? If it is, then there’s at least one unchanging truth, namely, the claim itself. If not, then the claim itself will change, and when it does, then there will be unchanging truths.

Truth is relative: If truth is relative, then the claim itself is only relatively true. It does not hold across the board, which means that truth is not necessarily relative.

Truth is created, not discovered: Was that truth created or discovered?

There are no truths: Then the statement itself is not true.

I think there were others, but I don’t remember what they were off the top of my head. I covered a few of them earlier in this post. I’m pretty tired now. I think I can study German if I don’t fall asleep. If you read this whole thing, then kudos to you. You’ve gone above and beyond the call of duty. Thanks for giving me a hearing.

Sam

Monday, September 26, 2005

knowledge by inductive reasoning

Inductive reasoning is where you reason from the specific to the general, unlike deductive where you reason from the general to the specific. Inductive reasoning depends on assumptions such as that the future will be like the past and that the universe is uniform. The scientific method is based on induction. It assumes that the future will be like the past. Experiments are performed and repeated over and over, and when a large enough sampling is taken, scientists conclude that the results that have been reached so far will also be manifest in the future. So, for example, if things always fall when we drop them, and they’ve always done that in the past, then they will probably also do that tomorrow.

As David Hume and many others before him have pointed out, the assumptions of the scientific method cannot be proved by the scientific method. How would you go about proving that the future will be like the past? The temptation is to say, “Well, the scientific method has always worked in the past, so surely it will work tomorrow,” but that begs the question because whether or not the future will be like the past is the thing we’re trying to prove. So the only way the scientific method can give us true information is if we assume the future will be like the past. It’s not even provable in principle. The scientific method is the least reliable way we can know things because it depends on the previous ways we can know things. It depends on the reliability of our sensory experience to give us true information about the world, and it depends on our intuitive knowledge of the uniformity of nature. No conclusion can be more reliable than the premises upon which it rests.

That’s why scientism is self-refuting. Scientism is the belief that scientific knowledge is the only knowledge we can have. If something is not demonstrated by the scientific method, then it can’t be known. That’s a self-refuting claim because the claim itself cannot be demonstrated by the scientific method.

It seems like we are well-justified in trusting inductive reasoning in general and the scientific method in particular to give us true information. What is remarkable is the fact that it seems we can be more certain about our knowledge of immaterial things than about material things since our knowledge at the intuitive level—the most reliable level—is full of knowledge about immaterial things like logic, minds, propositions, numbers, etc.

There are other ways we know things (e.g. knowledge by analogy is how we know solipsism is false), but those are the four major ways as I see it. Of course epistemology is a fairly broad area of philosophy.

Friday, September 23, 2005

knowledge by sensory perceptions

The third way we can know things is through sensory experience. Here, we are moving away from certainty because, as Descartes said, it is possible that our senses are deceiving us. Here is where I agree with Nietzsche in his criticism of some philosophers. The ironic thing, though, is that it is actually eastern philosophers who doubt the existence of the external world. Hindus think everything is maya, that is, illusion. Western philosophers generally accept the existence of the external world, so what Nietzsche’s real problem should be is with the fact that some western philosophers think the physical world is not all there is in reality. Here we notice something interesting. If we assume that our senses are giving us true information about the world, then what do we base that knowledge on? Do we base it on our sensory experience? No, we base it on our intuition. We just assume our senses are giving us true information. So those who claim that we can only have knowledge through our senses are making a self-refuting claim since their claim is not known through their senses. Since the claim is self-refuting, we know that it is false. Since it’s false, it cannot be the case that sensory experience is the only way we can know things. Intuition is the other way we can know, and we could not know anything through our senses if it were not for intuition to tell us that we should trust our senses.

But should we trust our senses? I think so. One of the arguments used against relying on our senses is the fact that we dream and the fact that we hallucinate. But look at it this way. If we are in a constant state of delusion, then how would we ever know that we had been hallucinating before or that we had been dreaming before? The only way we can know that is if we are not dreaming or hallucinating now. The fact that we make a distinction between dream and reality shows that we are not always dreaming. We are not always delusional.

Should we trust our intuition when it tells us to trust our senses? I think so. I asked one person in class whose name I can’t remember whether he thought it was more reasonable to believe that the world is maya or to believe the world is real. He said he didn’t prefer one over the other. But how many of you would walk out into moving traffic and ask, “What is reality anyway?” I suspect that when it comes down to it, you all believe very strongly in the physical world. And what reason is there not to? While it may be possible that we are being deceived, the fact that it is possible does not mean that it’s reasonable to believe. The external world stares us in the face every day, but the theory that the world isn’t really there is contrived. It’s just made up. Nobody lives consistently with the belief that the external world is an illusion because no matter how much we deny the physical world, we all live in it, and we all believe in it.

At this point, we can see how we are moving from certainty to doubt. Some of those things we knew intuitively are actually more certain that what we can know of the physical world. There is one last way of knowing that I’ll mention, and although it is said by some to be the most reliable way of knowing, it is actually the least reliable because it depends on the previous ways of knowing for it’s foundation. That is inductive reasoning.

[In a debate I had a couple of years ago, the person I was debating with said we can trust our senses, because everybody else around us is observing the same thing. If I see a green jeep, and everybody around me sees the same thing, then I should trust that my perception of the green jeep is accurate.

But this argument is question-begging. How do we know that there's anybody around us that sees what we see? Well, we can only know that through our senses. We have to see these other people, and we have to hear them when they tell us they see the same thing. The only way we can appeal to other people is if we assume already that our senses are giving us true information about the external world, and that begs the whole question.

Another person might say that our different senses themselves give us multiple attestation. If our nose, ears, eyes, and hands, all agree that the green jeep is there, I should trust them.

But this argument fails, too, because all of our sensory experiences take place in one and the same mind. When we dream, we see people talking and hear their voices at the same time, and yet it all goes on in the mind. If all of our senses are in question, then we can't appeal to any of them to justify the others. And we can't appeal to consistency either, because our mind produces consistent perceptions even when we're dreaming.]

Thursday, September 22, 2005

logic and language

The argument was made in class that logic was invented right along with language, which implies somehow that if we had just redone language, we could’ve also undone logic. If it is the case, however, that language actually conveys true information about ideas, then logic does not apply merely to language, but also to ideas, and if ideas can actually correspond to reality, then logic also corresponds to reality.

We can easily know that language actually does accurately convey ideas because the negation of that is self-refuting. The claim that “Language cannot convey meaning,” is self-refuting when understood. If language could not convey meaning, we would not be able to really understand what the statement meant or what the speaker meant by saying it. If Nietzsche makes the claim that language cannot convey meaning, and if we believe him, then it’s pointless for us to read him since we have no hope of understanding what he was trying to convey to us.

The fact that language conveys meaning is obvious. The other morning, I did another thought experiment with a co-worker named Donna. I said, “Donna, look at the TV,” and she turned her head and looked at the TV. Then I said, “Donna, look back at me,” and she turned her head and looked back at me. I had an idea of what I wanted her to do in my head, and I used language to convey that to her. Either my language accurately conveyed my thought to her, or else it was just a huge coincidence that she did exactly what I had envisioned. Which is more reasonable to believe?

One person in class rightly pointed out that language is a created system of tokens. A statement represents an idea, but it is not the idea itself. One proposition can be stated in a variety of different ways. You can state a proposition in different languages, and you can write it several times on a sheet of paper, but you’re still talking about the same proposition. The usefulness of language is in the fact that it can actually correspond to reality. Now if language can correspond to reality, then so does logic. If you claim that logic is a function of language, and that language corresponds to reality, then logic must also correspond to reality.

If logic did not apply to the real world, there would be nothing to prevent you from building a house that was bigger on the inside than the outside. Married bachelors might be as common as either single or married people. You could even exist and not exist at the same time. Everyone, including eastern philosophers who claim to subscribe to both/and thinking and reject either/or thinking use logic every day of their lives. Nobody walks out into moving traffic because they know it’s either them or the car, not both.

We would not be able to infer anything through deduction if not for intuition, for we must be able to recognize and know the laws of logic before we can use them. So logic and deduction depend on our intuitive knowledge.

[I might also point out that while a person can say things like "four-sided triangle," or "married bachelor," no such entities can exist in reality. You can say, "My cat is pregnant, and the same cat is also not pregnant," but your cat can't actually be both pregnant and not pregnant at the same time and in the same sense. That's because logic is not merely a function of language. Nor are the laws of logic merely laws of thought. They are laws of reality. It is because logic is a function of reality that we must think logically if our thoughts are to have any correspondence with reality.]

Wednesday, September 21, 2005

The logic challenge

If you’re still having your doubts about logic, then I have a couple of challenges for you. The first challenge is this: Take a piece of paper and draw a four-sided triangle. The second challenge is this: Take a piece of paper and draw three straight lines, labeled A, B, and C, such that A is longer than B, B is longer than C, and C is longer than A. When you fail, ask yourself why. (Hint: Both challenges entail logical contradictions.) You will notice that logic is not a mere matter of language. It actually applies to the external world. You need not search the universe to see if there are any four-sided triangles. You can already see that there aren’t just by noticing that a four-sided triangle is a contradiction.

[A few years ago, I started two threads on beliefnet where I made these two challenged to anybody who denied logic. I was going to post a link to those threads here, but I can't find them. If I find them, I'll post a link in the comments section.]

Tuesday, September 20, 2005

Paradox as a counter-example to logic, part 2

The second problem with using a paradox to disprove the laws of logic is that without the laws of logic, there wouldn’t even be such a thing as a paradox. So contrary to disproving logic, paradoxes actually prove logic. Take the barber paradox for example. The Barber paradox is where there’s this [ship] with a barber, and the barber shaves all and only those who do not shave themselves. But if the barber shaves all and only those who do not shave themselves, then who shaves the barber? If you think about that for a while, you’ll see the paradox. I’ll try to illustrate it, though. Let’s draw a box and say that the box represents everybody in town. We’ll draw a line down the middle of the box so that we divide it into two parts. There are only two kinds of people [on the ship]. There are those who shave themselves, and those who do not shave themselves.

Box A: Those who shave themselves.
Box B: Those who do not shave themselves.

The question now becomes: Which box does the barber go in? The barber shaves everybody in Box B, but he doesn’t shave anybody in Box A. If we put him in Box A, that means he shaves himself. But that can’t be because the Barber only shaves people in Box B, not Box A. But if we put him in Box B, then he does not shave himself. But that can’t be either, because he shaves everybody in Box B. See how we’ve got a paradox now? We’ve got nowhere to put the barber. Does he shave himself or not? Now notice that the only reason we’ve got a paradox on our hands is because we’re assuming the law of excluded-middle. Either people shave themselves, or they don’t. That’s why we’ve only got two boxes. Without the law of excluded-middle, we could have a third box labeled, “Those who both shave themselves and don’t shave themselves,” and then we’d have no paradox. So we can see that the existence of the paradox, far from disproving logic, actually shows us that logic is true. All the barber paradox shows us is that such a scenario could not be instantiated in the real world.

The same is the case with the liar paradox. [i.e. This statement is false.] The reason it’s a paradox is because logic is true. If logic were not true, the statement might make sense. As it is, the statement is meaningless and absurd because it’s neither true nor false. The reason we puzzle over it and can’t make sense out of it is because of logic.

Monday, September 19, 2005

Paradox as a counter-example to logic, part 1

One of the most popular ways to try to disprove logic is by bringing up paradoxes. A paradox is where a statement or scenario which appears to be meaningful actually gives absurd results. Take the liar paradox, for example. There are two ways of stating the liar paradox. One way is to say, “A: Statement B is true. B: Statement A is false.” Another way is to say, “This statement is false.” If you assume the statement is true, then it’s false, but if you assume it’s false, then it’s true. So is the statement true or false? According to the law of excluded-middle, it’s one or the other, but this statement appears to be both or neither. So it is often used as an argument against logic.

There are a couple of problems with using paradoxes as an argument against logic. The first problem is that it assumes logic while trying to disprove it, so it’s self-refuting. Whenever a person uses a paradox as an argument against logic, they are forming a syllogism.

1. If the laws of logic are true, they cannot be violated.
2. A paradox violates the laws of logic.
3. Therefore, the laws of logic are not true.

But if the laws of logic are not true, then the conclusion doesn’t follow from the premises since it requires logic to do so.

[There's another way to say the same thing. A paradox is usually brought up as a counter-example to logic. In other words the existence of a paradox is supposed to contradict the laws of logic, and the laws of logic are deemed invalid for that reason. The problem here should be obvious. If the laws of logic are invalid, then you can't dismiss them on the basis that a paradox contradicts them. You need the law of non-contradiction to do that.]

Friday, September 16, 2005

The law of excluded middle and self-refutation

The law of excluded-middle is a close cousin to the law of non-contradiction. While the law of non-contradiction tell us that a proposition and it’s negation cannot both be true, the law of excluded-middle tells us that either a proposition or its negation is true. So either my sister is pregnant, or my sister is not pregnant. One of those is true and the other is false. The negation of the law of excluded-middle is that a statement and its proposition are both true. In that case, my sister is both pregnant and not pregnant.

The problem with those who reject logic is that their arguments against logic are necessarily self-refuting, so before I show how that is so, I’ll explain what self-refutation is all about. A self-refuting statement is a statement that fails to meet its own standard for being true. All meaningful statements are about something. For example, the statement, “Steve teaches philosophy,” is about Steve. Some statements include themselves in their field of reference. For example, the statement, “All statements represent propositions,” is about all statements including the statement itself. A statement that is self-referential and that denies what it asserts is self-refuting. Here are some examples:

"I cannot speak a word of English," is self-refuting when spoken in English.

"All statements over five words long are false," is self-refuting because it is over five words long.

Self-refuting statements are necessarily false. Now the reason all arguments against logic are self-refuting is because they assume logic in their argument against logic. Take the denial of the law of non-contradiction for example. If a person says, “The law of non-contradiction is false,” then they are assuming that the person who believes in the law of non-contradiction is mistaken. But the only way to assume that is to use the law of non-contradiction, because otherwise, one could say that the law of non-contradiction is both true and false. But if the law of non-contradiction is true (which it must be if we are to deny it), then it is necessarily a mistake to deny the law of non-contradiction. So the law of non-contradiction is necessarily true, and denying it is self-refuting.

Denying the law of excluded middle is self-refuting for the same reason. Those who deny the law of excluded-middle say that either/or thinking is mistaken, and both/and thinking is correct. But in doing so, they are actually using either/or thinking. They are unwilling to say that BOTH either/or AND both/and thinking are correct. Instead, they are assuming that EITHER either/or OR both/and is correct, but not both, and they deny either/or thinking while accepting both/and thinking.

The only way to be consistent is to say that BOTH either/or AND both/and thinking are correct. But in that case, one is not denying the validity of the law of excluded-middle. Instead, one is affirming it. Since the law of excluded-middle excludes both/and thinking, then both/and thinking cannot be correct. If EITHER either/or thinking OR both/and thinking is correct, and if EITHER/OR thinking is correct, then both/and thinking is not correct. What we can see is that either/or thinking (the law of excluded-middle) is necessarily true, and both/and thinking is necessarily false because both/and thinking must include either/or thinking, and either/or thinking must exclude both/and thinking. Whether you begin by assuming either/or thinking or both/and thinking, you arrive at the conclusion that either/or thinking is correct, and both/and thinking is incorrect.

[Sorry I couldn't be more clear in this last paragraph, but if you'll just read it slowly and carefully, it make good sense. :-) Trust me.]

Thursday, September 15, 2005

Meaning and the necessity of the law of non-contradiction

That brings us to the definition of truth. Since we all know what a lie is, we also know what truth is. Truth is just the opposite of a lie. When we say that something is true, we mean that it actually corresponds to reality—the way the world really is. If I say my sister is pregnant, and she actually is pregnant, then I’ve told the truth.

[I wrote another blog about truth here.]

The reason I’m bringing this out is because it has a direct bearing on our reading of Nietzsche. I said before that unless we apply logic to our reading of Nietzsche, we might as well read his books backwards because without logic, none of it will make any sense. Whatever Nietzsche says, we must assume that he means something by it, and not its opposite. Without the law of non-contradiction, we have no way to make a distinction between what Nietzsche is saying and what he is not saying. It would be pointless for us to ask Steve to explain to us what Nietzsche means by something because whatever Steve tells us, we could also assume that it’s opposite is also the case. Just as it would be meaningless to you for me to say, “My sister is both pregnant and not pregnant,” so also would it be meaningless for us to read Nietzsche without the law of non-contradiction.

[The whole reason I went into this part about Nietzsche was because I had been criticizing Nietzsche for being illogical, and my philosophy teacher kept saying it was inappropriate for me to apply logic to Nietzsche.

I guess the whole point I'm making here is the same as I mentioned before--that significant speech is not possible without the law of non-contradiction. So nothing Nietzsche says can have any meaning unless we apply logic to it.]

Wednesday, September 14, 2005

The law of non-contradiction

The law of non-contradiction is one of the most obvious laws of logic, but one of the most frequently denied. It states that for any two propositions, if they contradict each other, they cannot both be true. Whenever I argue with people about the law of non-contradiction, they almost always resort to equivocation to get around it, but two statements can only contradict each other if they are talking about the same thing at the same time and in the same sense. Take the following two statements for example:

1. It is raining outside.
2. It is not raining outside.

A person who wants to argue against the law of non-contradiction may point out that both of these statements can be true provided that one is referring to Phoenix and the other is referring to Tallahassee. It may be raining in Tallahassee but not in Phoenix. But if we are talking about different places, then the statements don’t contradict each other, and consequently, they can both be true. If, however, they are both talking about the same thing, then they cannot both be true at the same time. Equivocation only gets you out of an actual contradiction; it doesn’t get you past the law of non-contradiction.

The law of non-contradiction is important because it’s how we tell the truth from a lie. Without it, there’s no such thing as a lie. A lie is that which contradicts the truth. After our lively discussion last Tuesday, I was all jazzed, so I went to work that night and talked to my co-worker, Julie, to get it off my chest. I said,

“Julie, let’s suppose I tell you that my sister is pregnant, and then five minutes later, you come to me and ask, ‘Does your sister know the sex of her unborn baby?’ I then reply, ‘My sister is not pregnant.’ What would you conclude from that?”
Julie said, “I’d say you’re crazy.”
“Why?”
“Because one minute you said your sister was pregnant, and the next minute, you said she wasn’t.”
“Would you assume I was lying?”
“Well yeah, duh!”
“But why would you assume that?”

She just looked at me like I had two heads, so I let her off the hook. I said,

“My sister is either pregnant or she’s not pregnant, right? She can’t be both pregnant and not pregnant at the same time and in the same sense, can she?”

Julie understood what I was getting at. It was something so obvious to her that she couldn’t deny it. If I say that my sister is pregnant, and yet she’s not, then I’ve told a lie. On the other hand, if I says she’s not pregnant, and yet she is, then I’ve told a lie. The reason for that is the law of non-contradiction. Both statements cannot simultaneously be true because they contradict each other. Whenever you encounter a contradiction, you can know for an undeniable fact that you are in the midst of error.

[Ronald Nash has a chapter in Worldviews in Conflict where he gives two arguments for the law of non-contradiction. One is basically the same as mine. Significant speach is impossible without the law of non-contradiction, because nothing we say means anything unless it excludes the negation of what we say. But he also argues that significant action is impossible without the law of non-contradiction. We cannot pay our taxes if there is no difference between paying our taxes and not paying our taxes. Nash gives a funny scenario in which the IRS confronts a guy who didn't pay his taxes. I don't have the book with me, but the guy said something like, "I learned in my philosphy classes in college that logic is not universally valid, so there's no difference between paying my taxes and not paying my taxes." The IRS responded, "Then there's no difference between going to jail and not going to jail."]

Tuesday, September 13, 2005

The law of identity

The law of identity states that whatever is, is, and whatever is not, is not. [Put some other ways, A=A. Or If A is true, then A is true.] It is often overlooked because it is a mere tautology. It’s true by definition. But there actually is a practical application to it. Suppose you’ve got two kids, and you come home one day and find that there’s a bowling ball that has smashed through the front of the TV. You know that one of the kids did it, but you’re not sure which one right away. Well the way you determine who did it is by applying the law of identity. The person who did it is the person who did it. So what you do is you take your two kids, sit them down on the couch, and you determine if the person who smashed the TV is identical to one of the persons sitting on the couch. Once you determined that whatever is true of one of the persons sitting on the couch is also true of the person who smashed the TV, then you know you’ve got the right person because they are identical. They are the same person. If you can discover something true of the person who smashed the TV that is not true of one of the persons sitting on the couch, then you can eliminate that person as a suspect. The law of identity is how we know that Steve is our philosophy instructor and not somebody else. If whatever is true of our philosophy instructor is also true of Steve, then Steve is our philosophy instructor. You can know that I am not the philosophy instructor because there is at least one thing that is true of the philosophy instructor that is not true of me.

[After Dale's question on yesterday's blog, I got to thinking that the law of identity is really used even more mundanely than the example above. We use the law of identity constantly. If you go in WalMart, you use the law of identity to find your car when you come back out. You use the law of identity to recognize people you know. You use the law of identity to make sense out of what people say. For example, when somebody says, "My dog barks," they don't mean, "My dog does not bark." They mean "My dog barks."]

Monday, September 12, 2005

knowledge by deductive reasoning, part 2

These basic syllogism are things we all use every day of our lives. Think of the last time you lost power in your house. How did you know when the power came back on? You probably knew it because maybe your lights came back on or something. When you make that inference, you’re using a syllogism.

1. If the power is not on, the light will not come on.
2. The light is on.
3. Therefore, the power is on.

It is actually almost impossible to think without using these syllogisms. The reason we are not consciously aware that we are doing it is because the first premise is hardly ever stated. It is assumed. Imagine having the following conversation:

Jim: Is the power on?
Bob: Yeah.
Jim: How do you know?
Bob: Because the lights are on.

Do you see how Bob is working with the assumption that If the lights are on, then the power is on? He doesn’t state it explicitly. It’s assumed in his reasoning. But without that assumption, Bob would not be able to conclude that the power was on just because the light was on. Using syllogisms is just a way of making explicit what is already implicit, and it’s useful in analyzing another person’s reasoning.


There is some reasoning we can immediately recognize as fallacious. Steve gave the classic example on our first class session. Suppose I said that Socrates is a man, and the reason I said he was a man was because he’s mortal. Can I really say that Socrates is mortal merely because he is a man? Of course not. The fact that he’s mortal doesn’t necessarily mean he’s a man. He might be a bird. Birds are also mortal. When a person makes an argument where the conclusion does not follow from the premises, that’s an invalid argument. In order for the argument to be valid, you would have to assume the hidden premise to be, “All mortals are humans,” or “If Socrates is mortal, then Socrates is a man.” In that case, the argument would not be sound because the first premise would be false. Those are the two ways a deductive argument can go wrong. If the conclusion does not follow from the premises, the argument is not valid. If one of the premises is false, the argument is not sound.

But in the classic argument, the first premise is that All men are mortal.

1. All men are mortal.
2. Socrates is mortal.
3. Therefore, Socrates is a man.

You can see that the conclusion does not follow. Socrates may in fact be a man, but we cannot know that simply by knowing that he is mortal. However, we can know that if Socrates is a man, then he is mortal, provided the first premise is true.

These syllogisms are one aspect of logic, and they are necessary to think or reason intelligibly. The other aspect is the three basic laws of logic, the law of identity, the law of non-contradiction, and the law of excluded middle. Steve mentions a fourth, which is basically the same thing as the law of identity stated in the negative.

[The best "intro to logic" I've seen is in chapter two of Philosophical Foundations for a Christian Worldview by J.P Moreland and William Lane Craig. It goes into more depth than mine does, and it's far more clearly written.]

Friday, September 09, 2005

knowledge by deductive reasoning, part 1

The second way we know things is through deductive reasoning. The second thing Descartes was unable to doubt was the fact that he existed. He inferred his existence from the fact that he was thinking. He reasoned that in order to think, he must also exist, because if he didn’t exist, he couldn’t think. He was basically using a syllogism known as a modus tollens, which goes like this:

1. If A, then B.
2. Not B.
3. Therefore, not A.

Descartes’ argument went like this:

1. If I do not exist, then I do not think.
2. I think.
3. Therefore, I exist.

(2) and (3) together are just the contrapositive of the first premise, so the modus tollens is just a different way of saying the modus ponens, which goes like this:

1. If B, then A.
2. B
3. Therefore, A.

How do we know that given the first two premises, that the conclusion follows? Well you can kind of see that just by thinking about it. Again, we go back to intuition. It is through our intuitive knowledge that we know the syllogism is valid. You only have to think about it to see it. There are two other syllogisms worth looking at. The next one is the disjunctive, which goes like this:

1. Either A or B.
2. Not A.
3. Therefore, B.

This one is also obviously true. Basically, the disjunctive syllogism is the same thing as the process of elimination. Given a set of live options, if you know first of all that one of the options is true, then all you have to do is eliminate all but one of the options. Then it would follow that the one remaining option is the true one. So you can actually have more than two options. For example, suppose you’re playing that game where somebody hides a pea under one of three shells. He mixes them all up so that you get confused, but at the end, you know the pea is under one of the shells. Suppose you look under two of the shells and the pea isn’t there. Where is the pea? Without looking under the third shell, and assuming nobody has magically removed the pea, you can deduce that the pea is under the third shell before you even lift the shell to see.

The fourth syllogism is the transitive property, which goes like this:

1. A = B.
2. B = C.
3. Therefore, A = C.

The transitive properties takes many different forms. Rather than using equal signs, you could use greater than or less than signs. It works just as well with propositions as it does with math because mathematical statements actually are propositions stated in a different language. Now let’s suppose there’s three people, Jim, Dan, and Bob. Assume you know that Jim is taller than Dan, and Dan is taller than Bob. What can you conclude about the height difference between Jim and Bob? Just think about it for a second. Picture it in your mind. Jim is taller than Dan. Dan is taller than Bob. Who is taller—Jim or Bob? Well, I think you can see that Jim is necessarily taller than Bob. You can see that merely by reflecting on it in your mind. You don’t have to know Jim, Dan, or Bob or even how tall they are. You just have to understand concepts like “taller than” and “shorter than.” You can tell that the transitive property holds across the board, too. It’s not like the scientific method where you have to test it over and over again to see that it’s true. You can already see it in your mind. With one hypothetical example used for illustration, you can know that it will always be true.

Thursday, September 08, 2005

knowledge by intuition

Usually when we think of justification, we think we have good reasons for thinking a thing is true. In other words, we infer it from reliable premises. But how do we know the premises are true? If we are not justified in believing the premises, then we cannot be justified in believing what we have inferred from the premises. Then we need further premises in order to say that we are justified in holding the original premises. One of two things can happen now. We can either get ourselves into an infinite regress trying to justify our premises, or we can arrive at some premises that we can know without having to prove them. If we get ourselves into an infinite regress, then we know nothing. So if we know anything at all, there must be some things we know but for which we have no proof.

That brings me to the first way we know things. We know them by intuition. I mentioned this in class the other day, and from the laughter that resulted, I was afraid I was being misunderstood. What I mean by intuition is not the same thing as when you think of women’s intuition, which is a subjective hunch that a certain thing is true. I’m not talking about the ability to draw conclusions based on some special kind of insight. What I’m talking about is immediate knowledge upon reflection. It’s the kind of knowledge you are immediately aware of without inference. If any of you have read Rene Descartes’ meditations, you’ll know what I’m talking about. Descartes was able to hypothetically doubt everything about the external world by assuming that there could be an evil genius deceiving him to give him sensory perceptions of a world that doesn’t really exist. The one thing that Descartes was not able to doubt, though, was that he was thinking. He may have been mistaken about what he was thinking, but he could not be mistaken that he was thinking. That he was thinking wasn’t something that he inferred from something else. It was something he knew immediately upon reflection.

There are many things we can know in this way even if we doubt everything else. We may doubt that our sensory perceptions are giving us true information about the world, but what we can’t doubt is that we are perceiving. Suppose I tell you that my hand is injured, and you ask me how I know. Then I say, “Because it hurts.” “But how do you know it hurts?” “Because I feel it.” “How do you know you feel it?” At this point, I’m at an impasse. I don’t infer that I feel it from something more basic. I know I feel it simply because I feel it. I’m immediately aware of my own feelings. [I borrowed this analogy from Relativism: Feet Firmly Planted in Mid-air by Greg Koukl and Frank Beckwith.]

So intuitive knowledge is a priori knowledge. It is knowledge we have upon reflection, but which is not inferred from anything prior. Without intuitive knowledge, it would be impossible to know anything else, since everything else we know is inferred directly or indirectly from what we know intuitively. Otherwise, we would have no knowledge. One of the things we know intuitively is logic, and that brings me to the second way we know things.

[Some day, I'm going to go into more detail about intuitive knowledge. I'm going to get more specific about what we know intuitively. It was some time after I wrote this that I began to break intuitive knowledge into three categories--things we know due to first person subjectivity, things that are rationally grasped, and things we know simply because of how a normally functioning mind works.]

Wednesday, September 07, 2005

What is knowledge?

[Here's the beginning of the email. I'm cutting off the first paragraph. I know, I know, you're thinking, "Hey, if you cut out the first paragraph, then how can this be the beginning of the email?" You have a point there. Okay, lemme rephrase myself. This is the beginning of most posts of this email. How's that?]

What I want to do is persuade you that logic applies to the real world, that it is necessary, that it is objective, that knowledge is possible, and that language is adequate to convey true information. Sounds pretty ambitious, eh? It is, because technically speaking, I can’t prove logic. (Actually Aristotle has an interesting "proof" of the law of non-contradiction.) To prove something, you have to infer it from things that are known. The laws of logic are rules of inference, so they themselves can’t be inferred without begging the question. Luckily for me, though, I don’t really need to prove logic because you already believe it. Everybody believes in logic, they just don’t realize it. All I need to do, then, is cause your intuition to rise to the surface so that you’ll realize that you already believe in logic.

We know different things in different ways. There are basically four different ways we can know things, and they vary in degree of certainty. But before I discuss how we know what we know, I should give a definition of "knowledge" so you’ll know what I’m talking about. People tend to use a different definition of "knowledge" when they talk about religion or abstract ideas than they do when they use it in their daily lives. When I was in high school, I somehow came to believe that knowledge was not possible. My argument was basically that we only have degrees of belief, but since our belief was never 100% without any degree of doubt, then we don’t have any knowledge. Although I held this idea when thinking abstractly, I was inconsistent in the fact that in my every day life, I still claimed to know some things. If somebody asked me, "Do you know what time it is?" I wouldn’t say, "No, I don’t, but I believe it’s 4 o’clock." Sometimes when talking to my friends, I would catch myself saying, "I know what you mean." In my day to day life, I was using a different definition of knowledge than what I was using when thinking abstractly. The definition I was using turned out to be the way philosophers ordinarily use the word. Knowledge is justified true belief.

That probably needs to be unpacked a little, so I’m going to borrow some analogies from David Sosa, one of my philosophy teachers at UT Austin, to show what I mean. Let’s say David plays the lottery, and he picks his numbers himself. For whatever reason, he becomes convinced that he’s going to win. He doesn’t just hope he’s going to win, he actually believes it. And then lo and behold, he wins! Now, did he know that he was going to win? Probably not, and the reason is because he had no justification for thinking that he was going to win. So it isn’t enough that we believe something which is true to claim that we know it. We must also be justified in holding the belief. David had no real justification for thinking he was going to win. He was just lucky. On the other hand, suppose David is on a jury, and the prosecution presents what appears to be an irrefutable case for the guilt of the man on trial. In that case, David is well-justified in proclaiming the man guilty beyond a reasonable doubt. But what if later DNA evidence frees the man? Can we say that David knew he was guilty? No, and the reason is because you can’t know something that isn’t true. It isn’t enough that your belief is justified, it must also be true. So knowledge is justified true belief.

[After reading this, I noticed I left something out. I said that "Knowledge is justified true belief." I talked about "justified" and about "true," but I didn't talk about "belief." Maybe I left it out because it seemed to banal a point. But it's important. Before you can claim to know something, you have to at least believe it. If a person claims to know that something is true but does not believe it to be true, then he's contradicting himself.]

Tuesday, September 06, 2005

knowledge and logic

About two or three years ago, I took a class on Nietzsche. Although I had heard plenty about Nietzsche I never could actually spell his name until I took that class. My philosophy professor did his dissertation on Nietzsche, which was called "A Buddhist Interpretation of Nietzsche." He said he had been reading Nietzsche since high school. Early on in the semester, I came to the realization that Nietzsche was an irrational nutcase, and I couldn't for the life of me understand why anybody took him seriously as a philosopher. My initial impression of Nietzsche was confirmed as the semester went on.

My professor opened up an email discussion for the class so that we could talk about whatever we wanted by emailing the whole class. Lots of interesting conversations and debates went on in there, and I found myself to be in the minority in most cases. I often criticized Nietzsche's sloppy arguments or lack of arguments, pointing out the many logical fallacies he committed, and I was constantly criticized for doing so. My philosophy professor seemed to think it was inappropriate to apply logic to Nietzsche, and he seemed to have the majority of the class convinced that logic was a matter of personal preference, and that I was merely arguing from a western biased point of view.

Since logic was so undervalued in that class, it was difficult to advance any sort of arguments. All of my arguments made use of logic. I often put them in formal form, such as disjunctive syllogisms, modus tollens, modus ponens, transitive, etc. My arguments were ineffective, not because anybody could find a flaw in my reasoning, or because anybody thought my arguments were unsound, but because they rejected the laws of logic they were based on. So all of these arguments always boiled down to the validity of logic.

Logic wasn't the only thing being attacked. My professor also attacked the correspondence theory of true, the notion that language can convey true information, and the whole notion of objective truth in general. It seemed the class was willing to accept this nonsense uncritically, and I often found myself just shaking my head.

In my frustration, I finally wrote a long email to the whole class defending logic. I said to them, "What I want to do is persuade you that logic applies to the real world, that it is necessary, that it is objective, that knowledge is possible, and that language is adequate to convey true information."

Since some of these issues have come up here in my discussions with Steve and Dale, I thought I'd reproduce a lot of that email here in the blog. Some of it probably needs to be rewritten, so I may edit parts along the way. That all depends on how lazy I am and how badly I think something needs to be rewritten. I don't know how much conversation this will generate since just about everybody who makes comments here seems to be reasonable people who basically already agree with me on these issues, but I think this email will give everybody a lot of insight into how my mind works. Dale once suggested I post something about my thought process. Although this may not really fulfill that suggestion, I think it will be a significant step in that direction.

Monday, September 05, 2005

Biblical argument for substance dualism

I do think a Biblical case can be made against substance dualism, but that case is not air-tight. Many of the passages (e.g. Ecclesiastes 9:5) could just as easily be used to build a case against resurrection. Some (e.g. Jehovah's Witnesses) are able to bring up dozens of passages showing that the word "soul" refers to any personal being, not to an immaterial self. They'll say we don't have a soul; we are one. But the words for soul and spirit are used in a variety of ways in the Bible, and they are arguably used to refer to the immaterial self in some passages.

There may be several places in the Bible that support substance dualism, but the case for substance dualism from those passages is not air tight. It's possible to interpret them in a way consistent with denying substance dualism. For example, some people use the parable about the rich man and Lazarus to argue for substance dualism, but this passage can be taken as a parable used by Jesus with no intention of explaining the reality of "life after death."

But there is one passage I think is about as air-tight as it's possible for a theological argument to be. 2 Corinthians 5:6-8 says,
So we are always confident, knowing that while we are at home in the body we are absent from the Lord. For we walk by faith, not by sight. We are confident, yes, rather to be absent from the body and to be present with the Lord.
If we do not have an immaterial self that survives the death of the body and is capable of disembodied existence, then how is it possible to be "absent from the body" while at the same time being "present with the Lord"? I don't think it is possible, so it seems clear to me that Paul is assuming substance dualism.

I'm not about to say that some possible answer couldn't be given to this argument. Though I have yet to hear one (i.e. one that doesn't ignore my point), I've been sitting here trying to think of one myself. I suppose a person could argue that by being "absent from the body," Paul is referring to the present body, and that by being "present with the Lord," he's referring to when we recieve our future resurrection bodies. After all, in chapter 5, Paul does use some phrases similar to phrases he uses elsewhere in reference to resurrection. For example, in verse 2, he says, "we groan," which is similar to what he said in Romans 8:23: "we ourselves groan within ourselves , eagerly waiting for the adoption, the redemption of our body." In verse 3 and 4, he talks about being clothed so that "mortality may be swallowed up by life," which is similar to 1 Corinthians 15:53,54, which says "this mortal must put on immortality," so that "death is swallowed up by victory." That whole passage in 1 Cor 15 is about the nature of resurrection.

Suppose, though, that the Bible is completely silent on the topic. Couldn't we still draw some conclusion through philosophical reasoning? The philosophical case for some form of substance dualism seems strong to me, which is why I'm a substance dualist.

Friday, September 02, 2005

Is resurrection consistent with substance dualism?

So far, I have only argued that living people have an immaterial aspect to their nature—a distinct substance we call a self, a mind, an ego, a spirit, or a soul. But whether the soul survives the death of the body is another question, and that’s what I’m going to talk about in this post.

I sort of posted on this before, and here is the post.

There’s a common objection that many people (especially Jehovah’s Witnesses) make against the idea that the soul survives the death of the body. They argue:

1. If we survive the death of the body and go to heaven or whatever, then there’s no point in having a resurrection of the dead.
2. There is a point to resurrection, because the resurrection of the dead to eternal life is the ultimate hope of Christians.
3. It follows that we do not survive the death of the body and go to heaven.

The problem here is with the first premise. While the first premise says that disembodied existence is inconsistent with resurrection, I will argue that resurrection is inconsistent with denying a disembodied existence between death and resurrection.

To make my argument, I’m going to use some thought experiments again. Some of these will sound a lot like my first argument.

First, let’s just think about what a resurrection is. I’m going to argue about this in a future blog, but for now, let’s just assume that a resurrection is when a physical body that has died comes back to life and is transformed into an incorruptible body. The body that rises is the same body that died, albeit transformed, and it’s a physical body. Moreover, everybody will be raised from the dead, both the righteous and the unrighteous according to Daniel 12.2.

Since both the righteous and the unrighteous will be raised, that includes both cannibals and their victims. Now let’s suppose a cannibal eat’s somebody and then dies a couple of days later. When you eat something, you absorb some of the molecules from that thing, and they become the building blocks of the cells in your body. To an extent, you are what you eat. Here’s the question, then: At the resurrection, who will get the molecules the cannibal got when he ate the other person? If the cannibal gets them, then the other person’s resurrected body won’t be completely identical with the body that died. But if the other person gets the molecules, then the cannibal’s resurrected body won’t be completely identical with the body that died. Either way, God must, to some extent, use new material to construct a resurrected body.

Jehovah’s Witnesses take this a step further and say that resurrection has nothing at all to do with the body that died. Even in the case of Jesus, they will say that Jehovah got rid of the body that was in the tomb, and the Jesus that appeared to the disciples only manifested a physical body for the sake of display, but it was not the same body that died.

Whether the JW’s are right or not, there must be some resurrections that will take place involving bodies made from new material other than the material of the dead body. Unless we have a soul that survives the death of the first body and reanimates the resurrection body, the person who rises at the resurrection is not the same person who died. That means for us, there is no resurrection. New people resembling us will be created, but we ourselves are done for at death.

This is not hard to see. I’ve already given the argument in an earlier blog. If all we are is the sum of our physical parts, then we cease to exist when those physical parts die. If a new body is formed, be it ever so like the body that died, then it will be a different person, even if that new person has all the same thoughts, emotions, temperament, memories, and sense of self.

But a couple of thought experiments also help to see this. According to JW’s, God remembers us perfectly when we die. He is able to remake us from his perfect memory at the resurrection. Now think about this. God is all-knowing, right? That means his perfect memory of us after we die is no different than his perfect knowledge of us before we die. He has perfect knowledge of us both before and after we die.

If God is able to remake us from his memory ten minutes after we die using materials other than our dead body, then he could do the same before we die. He would use material that already existed before we died to make a new body from his perfect memory of us. But he could just as easily use that same material to make a new body from his perfect knowledge of us before we die. But obviously, one person can’t be in two places at the same time. What we’d have is two distinct persons—one original and one replica. The replica would not know the difference, either. If God even created all his mental states exactly the same as the original, the replica would think he was the original.

If God really does raise us from the dead by creating a new us from his memory after we die, then what he’s doing is making a replica of us. He isn’t really raising us. He’s just making copies.

Look at it another way. If God can use any material to make us another body at the resurrection, then he could just as easily make two identical bodies from his perfect memory of us. But they can’t both be the same person, because one person can’t be in two places at the same time. So these are two different persons. Which one is the original? Well, neither is the original! They’re both copies.

The only way to maintain continuity of identity between death and resurrection is if the person who owned the body that died survives and is the same person who owns the body that rises. And the only way it can be the same person is if that person survives the death of the body and endures to reanimate the body that rises. So a real resurrection of those who die is only possible if we continue to exist between death and resurrection, which entails that we must have an immaterial self capable of disembodied existence. We must have a soul if we are to have any hope of a resurrection.

Thursday, September 01, 2005

The rational argument for substance dualism

In the third chapter of his book on Miracles, C.S. Lewis argued that rationality is only possible if we have a soul or a mind that is distinct from the brain. If all we are is physical stuff, then we cannot be rational. If Lewis is right, then it is self-refuting for a person to deny substance dualism. By denying substance dualism, he also denies the necessary preconditions for rational thought, which means that even his denial cannot be rational.

I can never hope to be as clear and articulate as C.S. Lewis, so I really urge you all to go to the library and read chapter three in his book. Or go to the Christian book store or Barnes and Noble and sit down on the floor and read it. It’ll just take you a few minutes.

In the meantime, I’m going to explain it as best I can. I think it meshes perfectly with J.P. Moreland’s argument. I had to tweak Moreland’s argument in the last blog. His argument went basically like this:

1. If the mind is merely a result or property of the brain, then we could not have free will.
2. We do have free will.
3. Therefore, the mind is not merely a result or property of the brain.

I had to tweak Moreland’s argument, because I don’t believe in libertarian free will like he does, and I don’t think libertarian free will is necessary to make the argument work. All that’s necessary is that the will have causal influence over the brain. My argument would look more like this:

4. If the mind is merely a result or property of the brain, then we could not act intentionally.
5. We do act intentionally.
6. Therefore, the mind is not merely a result or property of the brain.

What Moreland and I agree on, though, is that if the mind is merely the result or property of brain chemistry, then strict causal determinism is true. This isn’t hard to see. Let’s suppose that all that exists is physical stuff--matter and energy. If so, then all causal interactions in the brain are caused by the net forces acting on each molecule in the previous instant in time. Each brain state is caused by a previous brain state plus any other outside interference, such as signals reaching the brain through our senses, chemicals, or knocks on the head. Since each brain state is caused by something else physical, and every physical event is caused by previous physical events, all the events in the brain are determined by what caused them.

Since all the brain events are causally determined, all the mental events associated with those brain events are also determined. That includes the process of thinking and reasoning. The reason one person believes as he does and another person believes differently is because the causal interactions in one of their brains resulted in one belief and the causal interactions in the other’s brain resulted in a different belief.

Effects follow necessarily from their causes, so any person’s beliefs would have arisen whether there were good grounds for thinking it is true or not. It is completely irrelevant that one idea follows logically from another idea. Each idea is merely the effect of deterministic chemical reactions. Though we have a sense that we have arrived at a conclusion through sound reasoning, in reality, each step of the reasoning process is just the result of brain chemistry.

Lewis makes this clear by making a distinction between two senses of the word “because.” If we say Grandfather threw up because is ill, we are using the cause and effect sense of the word “because.” Being ill is what caused Grandfather to throw up. But if we say Grandfather is ill because he’s been throwing up, we are using the ground and consequent sense of the word “because.” His throwing up is the grounds upon which we think that he must be ill.

Our process of reasoning can only be valid if our conclusion is the consequent of good grounds. But if our conclusions are always arrived at by being the effects of causes, then they would arise whether there were good grounds or not. The fact that there may be good grounds for some conclusion is irrelevant to whether or not the conclusion is arrived at.

Strict physicalism is self-refuting, because if it is true, then we cannot be rational in believing in physicalism. The difference between a physicalist and a substance dualism is not that one is rational and the other is not, but that a series of blind causal interactions eventually resulted in one belief in the physicalist and a different belief in the substance dualist.

By affirming either position, we must assume substance dualism, because substance dualism is the only way we can make our affirmation rationally. In substance dualism, metal states (such as the belief that All men are mortal and the belief that Socrates is a man) can cause other mental states (such as Socrates is mortal) because one can mentally “see” the logical relation between these beliefs and draw a conclusion through mental processes.