Before I start an analysis and evaluation of Thomas Aquinas’s Unmoved Mover argument, I want to finish evaluating Norman Geisler’s Thomist Cosmological Argument (hereafter: TCA) in When Skeptics Ask (hereafter: WSA).  In Part 4 of this series,  I showed that the very brief argument Geisler gives in support of the first premise of TCA is a stinking philosophical TURD.

But Geisler gives a more detailed and in-depth defense of the first premise of TCA in his older book Philosophy of Religion (hereafter: PoR).  So, before we can write off premise (1) of TCA, we should consider what he has to say in support of that premise in Chapter 9 of PoR.

Here is Geisler’s argument in PoR (p.191) for the claim that “something exists”, which is part of what premise (1) asserts: 

Here are the key claims in this argument in Geisler’s own words:

11. It is actually undeniable that something exists.

12. I exist.

13. Any attempt to deny one’s own existence is self-defeating.

14. One always (implicitly) affirms his own existence in the very attempt to deny it.

15. One must exist in order to make the denial.

16. If he exists, the denial is not true.

17. All attempts to deny the existence of everything self-destruct.

18. It is necessary to affirm that something exists.

The above claims could use some clarification:

11a. It is undeniable that something exists.

12a. Norman Geisler exists.

13a. Any attempt by a person to deny his/her own existence is self-defeating.

14a. A person implicitly affirms his/her own existence in any attempt by that person to deny his/her own existence.

15a. A person must exist in order for that person to deny his/her own existence.

16a. IF a person exists, THEN the denial by that person of his/her own existence is not true.

17a. All attempts by a person to deny the existence of everything are self-defeating.

18a.  Something exists.

Geisler is not at all clear about the logical structure of this argument, but I will attempt to re-construct his reasoning.  I think the basic structure of the argument goes like this:

15a. A person must exist in order for that person to deny his/her own existence.

THEREFORE:

H. IF a person denies his/her own existence, THEN that person exists.

16a. IF a person exists, THEN the denial by that person of his/her own existence is not true.

THEREFORE:

I. IF a person denies his/her own existence, THEN the denial by that person of his/her own existence is not true.

J.  IF the denial by a person of his/her own existence is not true, THEN the affirmation of  that person’s existence is true.

THEREFORE:

K. IF a person denies his/her own existence, THEN the affirmation of that person’s existence is true.

THEREFORE:

14a. A person implicitly affirms his/her own existence in any attempt by that person to deny his/her own existence.

THEREFORE:

13a. Any attempt by a person to deny his/her own existence is self-defeating.

L. When a person denies the existence of everything, that person is denying his/her own existence.

THEREFORE:

17a. All attempts by a person to deny the existence of everything are self-defeating.

THEREFORE:

11a. It is undeniable that something exists.

THEREFORE:

18a.  Something exists.

NOTE: I don’t see what logical role premise (12a) has in this argument.  It might just be pointing to a specific example that one could use to walk through the logic of the argument, which involves universal generalizations (e.g. “any attempt”, “one always”, “all attempts”).  Geisler exists.  But what if he denies his own existence?  In that case, he must exist in order to be able to deny his existence, according to premise (15a), and so on.  I believe that we can toss premise (12a) aside without damaging this argument.

Here is an argument diagram showing the logical structure of Geisler’s argument for the conclusion that “Something exists”:

This seems like a very complicated argument for the very simple claim that “Something exists”.  I wonder if the basic premises of this argument are any more obvious or certain than the claim that “Something exists”.  If not, then this argument has no value or significance.  The premises of an argument need to be more obvious and more certain than the conclusion, at least in the case of deductive arguments (with inductive arguments you can arrive at a conclusion that has a high degree of probability even if some of the premises have only a modest degree of probability).

EVALUATION OF GEISLER’S ARGUMENT FOR “SOMETHING EXISTS”

Geisler’s argument starts with this initial inference:

15a. A person must exist in order that person to deny his/her own existence.

THEREFORE:

H. IF a person denies his/her own existence, THEN that person exists.

Premise (15a) is clearly and obviously TRUE, and the inference seems to be VALID.*  I’m not sure that (15a) is any more obvious or certain than (H), but since both seem obvious and certain, I won’t quibble about this infrence.  I do have one caveat here, though.  One can deny one’s own existence at time t1, and if so, then one must exist at time t1, but then one could cease to exist and thus no longer exist at time t2.  So, there is an implicit reference to time in both (15a) and (H).

Here is the next inference in Geisler’s argument:

H. IF a person denies his/her own existence, THEN that person exists.

16a. IF a person exists, THEN the denial by that person of his/her own existence is not true.

THEREFORE:

I. IF a person denies his/her own existence, THEN the denial by that person of his/her own existence is not true.

This inference from (H) and (16a) is a hypothetical syllogism and is clearly deductively VALID.  Premise (H) is obviously and certainly TRUE.  So, the main question is whether premise (16a) is also TRUE.  This premise is also obviously and certainly TRUE, so this deductive argument is SOUND.  Premise (I) also appears to be obviously and certainly true, even apart from the argument, so I’m not sure if this argument does any real work.  But since both premises appear to be obviously and certainly TRUE, I won’t quibble about this deductive argument.  (I don’t know if this matters, but all three claims here have an implicit reference to time, because a person can exist and one point in time, but then cease to exist, and thus not exist at a later point in time.)

Here is the next inference in Geisler’s argument for “Something exists”:

I. IF a person denies his/her own existence, THEN the denial by that person of his/her own existence is not true.

J.  IF the denial by a person of his/her own existence is not true, THEN the affirmation of  that person’s existence is true.

THEREFORE:

K. IF a person denies his/her own existence, THEN the affirmation of that person’s existence is true.

Premise (I) is clearly and certainly TRUE, and this is another hypothetical syllogism, so the inference from (I) and (J) to (K) is a deductively VALID inference.  The main question here is thus whether premise (J) is TRUE.  Premise (J) seems to be true, but I have a concern about the shift from “the denial…is not true” to “the affirmation…is true”.  In arguments about the existence of God, such a conditional claim would NOT be acceptable:

X. IF the denial of the existence of God is not true, THEN the affirmation of the existence of God is true.

In the case of the existence of God, there is a third possibility:

Y. The sentence “God exists” is neither true nor false.

One of the biggest objections to theism in the twentieth century was that the sentence “God exists” does NOT assert a factual claim, a claim that could be true or false.  If we understand the denial of the existence of God to mean agreement with the sentence “It is not the case that God exists”, then that denial could also be said to be neither true nor false.

So, a person who was skeptical about theism on the basis of this sort of objection would say that “the denial of the existence of God is not true” and would also say that “the affirmation of the existence of God is not true“.  Such a skeptic would reject the conditional statement (X) above.  Furthermore, so long as statement (Y) is a logical possibility, then we must all reject the conditional statement (X) above, because that statement assumes that there are only two possibilities: either “God exists” is TRUE or “God exists” is FALSE.

It is not immediately obvious whether this objection concerning the statement “God exists” applies to this particular case, however.  Maybe now we can make use of Geisler’s claim “I exist”, or stated more clearly:

2a. Norman Geisler exists.

Are there only two possibilities with this existence claim?  Let’s consider the parallel with the above conditional statement:

X1. IF the denial of the existence of Norman Geisler is not true, THEN the affirmation of the existence of Norman Geisler is true.

Could a skeptic assert an objection to (X1) that is analogous to the above objection (Y)?

Y1. The sentence “Norman Geisler exists” is neither true nor false.

Of course, anyone could utter the sentence (Y1), but the question is whether this is a meaningful thing to say.  Is it possible that the sentence “Norman Geisler exists” could fail to assert a factual claim, i.e. a claim that was either true or false? It is hard to imagine how this existence claim could fail to assert a factual claim.

I suppose that it is possible that this sentence could be partially true and partially false.  For example, if we think of Norman Geisler as being the co-author of When Skeptics Ask and being the author of Philosophy of Religion, it could turn out that he was the author of Philosophy of Religion but contributed nothing to the book When Skeptics Ask (perhaps he bribed the “co-author” to do all the work but to give him part of the credit).  In that way, the Norman Geisler who we thought existed only partially exists.

On this scenario, there is a a man who was the author of Philosophy of Religion, but there is no man who is both the author of Philosophy of Religion and the co-author of When Skeptics Ask.  But in this sort of case, we would normally conclude that “Norman Geisler exists” but that we had a partially mistaken understanding of what Norman Geisler has done, and thus a partially mistaken understanding of who Norman Geisler is.  There would still presumably be a birth certificate somewhere that recorded the birth of Norman Geisler (or if he changed his name, the birth of the person who later changed his name to: Norman Geisler).

But perhaps I am thinking too narrowly here, too much in keeping with our ordinary common-sense view of the world.  What if I am a brain in a vat and my sensory experiences are being generated by a powerful computer?  In that case, it seems very likely that there is no such person as “Norman Geisler”.  Norman Geisler is merely one of millions of imaginary, unreal persons, animals, plants, and objects that a computer creates in my mind.  I might firmly believe that “Norman Geisler exists” but that belief is based on a deception or delusion, and it is a FALSE belief.  I might fail to figure out that the statement “Norman Geisler exists” is FALSE, but it would, nevertheless, in fact be false, and thus would be a factual claim, a claim that could be true or false.

In the movie The Matrix millions of people were brains in vats (so to speak), and a super-powerful computer allowed these millions of people to interact in a virtual world created by the computer.  So, in a reality like that of The Matrix, the statement “Norman Geisler exists” could be true, even though all of my interactions with Geisler were in a virtual world created by a computer.  Nevertheless, there would be an actual human person, on this scenario, whose mind I would be interacting with, even though the actual body of Norman Geisler might look completely different than the Norman Geisler with whom I have interacted.  In any case, I would still be inclined to say that “Norman Geisler exists” even if all of my interactions with him turned out to be in an imaginary virtual world.

Here is another idea.  Norman Geisler is a dualist.  He believes that every human beings is composed of a body combined with an immaterial soul.  Thus, he believes that he himself is composed of a body combined with an immaterial soul.  So, when he asserts “I exist” (and when I re-state that claim as “Norman Geisler exists”), perhaps what he MEANS is this:

2b. There exists a person named Norman Geisler who is composed of a body and an immaterial soul. 

If that is what Geisler MEANS, then one could argue that the claim “Norman Geisler exists” has a problem that is very similar to the claim “God exists”, namely it makes the sort of metaphysical assertion that fails to make a factual claim, and that is neither true nor false.

The sentence “This body contains the immaterial soul of Norman Geisler” might not make a factual claim.  This sentence might be neither true nor false.  Nevertheless, I think that if someone could persuade Geisler that the sentence “This body contains the immaterial soul of Norman Geisler” (uttered while pointing at Norman Geisler) does NOT make a factual claim, and is neither true nor false, Geisler would still maintain his own existence.  He would probably say “I still believe that I exist, it is just that I had a mistaken notion about the nature of myself.”  So, I don’t think that (2b) is a correct interpretation of (2a), even though Geisler is a dualist, even though he currently believes that he is composed of a body plus an immaterial soul.

I’m having a difficult time coming up with a way of making sense of how it could possibly be the case that the sentence “Norman Geisler exists” could fail to assert a factual claim that is either true or false.  Perhaps this is a failure of my imagination, but I’m going to admit defeat here, and conclude that the sentence “Norman Geisler exists” (unlike the sentence “God exists”) clearly makes a factual claim and must be either true or false.  So, although I was previously hesitant to simply accept premise (J) of Geisler’s argument,  I’m now willing to believe that premise (J) is TRUE, and thus that the deductive argument from premises (I) and (J) to (K) is a SOUND argument.

However, because it required a fair amount of thinking to arrive at agreement with (J), and because I am not entirely certain that (J) is TRUE, I am inclined to raise the objection here that the truth of (J) is LESS obvious and LESS certain than the conclusion that “Something exists”.  So, although Geisler has, so far, provided SOUND deductive arguments in a chain of reasoning leading towards the conclusion that “Something exists”,  I don’t think this argument is successful, because it makes use of at least one premise that is LESS obvious and LESS certain than the conclusion of the argument.

The next inference in Geisler’s argument goes like this:

K. IF a person denies his/her own existence, THEN the affirmation of that person’s existence is true.

THEREFORE:

14a. A person implicitly affirms his/her own existence in any attempt by that person to deny his/her own existence.

I’m willing to accept premise (K) as TRUE, because it was validly deduced from two premises that I believe to be TRUE, although I don’t think (K) is as obvious or as certain as the ultimate conclusion of this argument (“Something exists.”).

Does premise (K) logically imply (14a)?  It seems to provide support for (14a), but this is NOT a formally valid deductive inference.  For one thing, there is a new term introduced by (14a): “implicitly affirms”.  There is also a shift from talking about a person who “denies his/her own existence” to talking about “any attempt” by a person “to deny his/her own existence”.

Because of the new terms and concepts introduced in (14a) it is NOT obvious or self-evident that (K) logically implies (14a).  Perhaps if we think carefully about this inference we will arrive at the conclusion that (K) does in fact logically imply (14a), but this again raises the concern that a part of Geisler’s argument is LESS obvious or LESS certain than the conclusion of the argument.  If we have to engage in a significant bit of thinking to determine whether (K) logically implies (14a), then this inference might well be a second weakness in the argument, making the truth of (14a) LESS obvious or LESS certain than the truth of (K), which already is LESS obvious or LESS certain than the conclusion of the argument.

In short, every time we encounter a premise or inference that is less than clearly obvious or clearly certain, we depart further from the requirement (for deductive arguments) that the components of the argument be MORE obvious and MORE certain than the conclusion of the argument.  So, if the inference from (K) to (14a) is something less than clearly obvious and clearly certain, then the failure of this argument will be doubly confirmed.

I’m going to set aside my reservations about the introduction of the phrase “any attempt” in premise (14a).  That is to say,  I will grant the assumption that if a person’s denial of his/her own existence necessarily involves that person implicitly affirming his/her own existence, then it would ALSO be the case that “any attempt” by a person to deny his/her own existence necessarily involves that person implicitly affirming his/her own existence.  I will assume here that “any attempt” at such a denial would be equivalent to in fact making such a denial.

That leaves just one potential problem with the inference to premise (14a), the introduction of the previously unused phrase “implicitly affirms”.  It is not immediately clear or obvious what it means to “implicitly affirm” a claim or statement.  So, as it stands, the inference from (K) to (14a) is formally INVALID.  We need a premise that defines or specifies sufficient conditions for when a denial of a claim involves implicitly affirming that claim:

M. IF a person’s denial of claim R logically implies that the affirmation of claim R is true, THEN that person implicitly affirms claim R in any attempt by that person to deny claim R.

K. IF a person denies his/her own existence, THEN the affirmation of that person’s existence is true.

THEREFORE:

14a. A person implicitly affirms his/her own existence in any attempt by that person to deny his/her own existence.

If it takes you a minute to try to wrap your mind around the complex claim (M), that should be an indication of the less-than-perfectly obvious and certain nature of this part of Geisler’s argument.  I’m still unclear and unsure about what the phrase “implicitly affirms” MEANS.

I can accept premise (M) as being a part of some yet-to-be fully explicated stipulative definition of the meaning of “implicitly affirms”.  But so long as the imagined stipulative definition remains incomplete and unstated, we can understand this phrase ONLY in terms of the sufficient condition stated in (M).  We must be vigilant against any inferences based on any implications of the phrase “implicitly affirms” that go beyond the partial definition that (M) provides.

I conclude that this revised sub-argument is SOUND, but given the complexity of (M), I think this part of Geisler’s argument further reduces the degree of obviousness and certainty of the conclusion.  So we now have identified two different parts of Geisler’s argument that are LESS obvious and LESS certain than the conclusion of the argument. Premise (J) is somewhat problematic, which makes the truth of premise (K) LESS obvious and LESS certain than the conclusion that “Something exists”, and the inference from (M) and (K) to (14a) is also somewhat problematic. Thus, the truth of premise (14a) is clearly LESS obvious and LESS certain than the conclusion “Something exists”.

Let’s continue and see if there are any other problems with Geisler’s argument for “Something exists”:

14a. A person implicitly affirms his/her own existence in any attempt by that person to deny his/her own existence.

THEREFORE:

13a. Any attempt by a person to deny his/her own existence is self-defeating.

Here we have yet another inference that is clearly NOT formally VALID.  Premise (13a) introduces a term that has not been used previously in the argument:  “self-defeating”.  Furthermore, just as Geisler failed to clarify or define the phrase “implicitly affirms”, he also failed to clarify or define the phrase “self-defeating”.  Given this context, I can probably construct a stipulative definition of “self-defeating” that will allow us to repair this part of Geisler’s argument, and turn it into a formally VALID inference:

 N. IF a person implicitly affirms claim S in any attempt by that person to deny claim S, THEN any attempt by that person to deny claim S is self-defeating.

14a. A person implicitly affirms his/her own existence in any attempt by that person to deny his/her own existence.

THEREFORE:

13a. Any attempt by a person to deny his/her own existence is self-defeating.

I’m willing to accept premise (N) as a stipulative definition of part of the meaning of “self-defeating”, as applied to denials of claims.  And given that premise, this argument appears to be VALID and SOUND.

Hang in there! We are getting close to the end of Geisler’s very complex argument for the very simple claim that “Something exists”.

TO BE CONTINUED… 

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* NOTE ABOUT PREMISE (15a)

Shortly after publishing this post, I realized that there was in fact a problem with premise (15a).  I think the problem is related to the fact that there are lots of implicit (unstated) references to time in this argument.  If so, the problem with (15a) is probably not a serious one, but I want to point it out anyway, just in case something later in the argument hinges on a reference to time.

Does Aristotle deny that an actual infinity can exist?  Many would say: “Yes, Aristotle denies that an actual infinity can exist.”  But now consider premise (15a):

15a. A person must exist in order for that person to deny his/her own existence.

This initial premise of Geisler’s argument in support of the claim “Something exists” appears to be based on a more general assumption:

O. A person must exist in order for that person to deny ANY CLAIM whatsoever.

But given (O) and our previous claim about Aristotle, we can formulate a VALID deductive argument with a FALSE conclusion:

1. Aristotle denies that an actual infinity can exist.

O. A person must exist in order for that person to deny ANY CLAIM whatsoever.

THEREFORE:

2. Aristotle exists.

It’s true, to the best of my knowledge, that Aristotle existed at one time in the past, more than 2,000 years ago.  But Aristotle no longer exists.  He is no more.  He died a long long time ago.  So, the conclusion of this apparently VALID deductive argument is FALSE.  Thus, to the extent that one agrees with premise (1), and many people would agree with that premise, that casts doubt on the truth of premise (O).

The way to fix this argument, it seems to me, is to introduce clear references to time.  The verb “denies” is present tense, but what we MEAN by premise (1) is that Aristotle made this denial a long time ago, and wrote it down in a book that gives us access to his beliefs and views today.  When premise (O) asserts that a person must exist in order to deny a claim, it means that the person must exist WHILE that person denies the claim, but then after denying the claim could have a massive heart attack, die, and cease to exist, or after denying the claim the person could be annihilated by God (if there is a God) and thus cease to exist.