Geisler’s Five Ways – Part 8: The Design of the Human Brain
The third argument in Phase 2 of Geisler’s case for God is another development of his argument from design, and it has many of the same problems as the second argument in Phase 2.
Here is the third argument, sticking closely to the words used by Geisler:
ARGUMENT #3 of PHASE 2
26. God designed our brains. (WSA, p.26)
27. IF God designed our brains, THEN God knows everything there is to know about the way we think. (WSA, p.26)
THUS:
28. God knows everything there is to know about the way we think.
29. IF God knows everything there is to know about the way we think, THEN God had great intelligence.
THEREFORE:
30. God had great intelligence.
Once again Geisler misuses the word “God”, making his argument unclear and confusing. Geisler is trying to make a case for the existence of God, so to assert that “God designed our brains” as a premise in his argument for the existence of God blatantly begs the question at issue. That is, if Geisler was using the word “God” in it’s normal sense, then premise (26) would clearly commit the fallacy of begging the question.
But Geisler does NOT believe that he has proven the existence of God (in the nomal sense of the word) at this point in his argument. He does think that his initial argument from design proved the existence of “a Great Designer of the universe”. So, when Geisler uses the word “God” here, he probably means “the designer of the universe”.
To avoid confusion, the word “God” needs to be stripped out of this argument and replaced with the phrase “the designer of the universe”:
ARGUMENT #3 of PHASE 2 (Rev.A)
26a. The designer of the universe designed human brains.
27a. IF the designer of the universe designed human brains, THEN the designer of the universe knows everything there is to know about the way humans think.
THUS:
28a. The designer of the universe knows everything there is to know about the way humans think.
29a. IF the designer of the universe knows everything there is to know about the way humans think, then the designer of the universe had great intelligence.
THEREFORE:
30a. The designer of the universe had great intelligence.
But Geisler’s conclusion in this part of Phase 2 is that “whatever caused the universe…had…great intelligence.” (WSA, p.26) So, once again, he needs premise (25), which he also needed in Argument #2 of Phase 2:
25. Whatever being caused the universe to begin to exist is also the designer of the universe.
From the combination of (30a) and (25), Geisler can infer his desired conclusion:
31. The being that caused the universe to begin to exist had great intelligence.
Because Argument #3 of Phase 2 requires premise (25), this argument FAILS, because premise (25) is questionable, and because Geisler FAILS to provide any reason whatsoever to believe that (25) is true. Because this argument rests upon (25) it FAILS, just like Argument #2 of Phase 2, which also rested upon (25).
Here is a diagram of Argument #3 of Phase 2 (Rev.A), with the conclusion at the top, and the supporting premises below it:
The other main premise of this argument is (30a), but this premise is obviously controversial and needs to be supported with a strong reason or argument. Accordingly, Geisler provides us with an argument in support of (30a):
28a. The designer of the universe knows everything there is to know about the way humans think.
29a. IF the designer of the universe knows everything there is to know about the way humans think, THEN the designer of the universe had great intelligence.
THEREFORE:
30a. The designer of the universe had great intelligence.
The inference in this argument is logically valid (a standard modus ponens), so the only question we need to consider is whether both premises are true.
Is premise (29a) true or false? This premise is clearly FALSE, because there is a break in the logical connection between the antecedent and the consequent. The antecedent uses the present tense verb “knows”, while the consequent uses the past tense expression “had great intelligence”. So, the time-frames don’t match up.
The fact that Joe knows calculus NOW, after passing the final of his third semester of calculus classes does NOT show that Joe “had a good grasp of calculus” when he was six years old, and just starting elementary school. People can learn things and grow in knowledge and intelligence over time. Similarly, even if the designer of the universe has a lot of knowledge NOW, this proves nothing about the knowledge or intelligence of the designer of the universe a thousand years ago, or a million years ago (the human brain has been around at least one million years).
Geisler screwed up the reference to time frames in this argument, because he is a sloppy and unclear thinker. The key time-frame that he FAILED to clearly point out and designate is this: when the human brain was being designed. If there was a being who was “the designer” of the human brain, and if the design for the human brain was developed at some point in time (at least one million years ago), then “the designer” of the human brain must have had the required level of knowledge and intelligence to create such a design at the time when the design for the human brain was being produced. For all we know, the designer of the human brain might have had less knowledge or intelligence prior to that time, and might have declined in knowledge or intelligence after the design of the human brain was completed.
For premise (29) to have any chance of being true, the time-frame in the antecedent must correspond to the time frame in the consequent:
29b. IF the designer of the universe knew (when the human brain was being designed) everything there was to know about the way humans think, THEN the designer of the universe had great intelligence (when the human brain was being designed).
And for premise (28) to affirm the antecedent of (29b), it must be modified to also refer to the same time frame:
28b. The designer of the universe knew (when the human brain was being designed) everything there was to know about the way humans think.
The conclusion of this modus ponens inference must also be modified to refer to the same time-frame:
30b. The designer of the universe had great intelligence (when the human brain was being designed).
What about premise (29b)? Is it true or false? Since we have revised the premise so that the time-frame reference in the antecedent matches the time-frame reference in the consequent, I see no reason to doubt or reject (29b).
So, the question of whether to believe that (30b) is true or false rests upon whether we believe that premise (28b) is true or false. Premise (28b) is a controversial claim, and it is not obviously true, nor is it a necessary analytic truth. In fact, as we will see later, there is a very good reason to doubt that (28b) is true. But Geisler has provided us with an argument for (28b), so we need to examine that argument. First we need to modify the time-frame reference in the consequent of premise (27), so that the inference to (28b) will be logically valid:
26a. The designer of the universe designed human brains.
27b. IF the designer of the universe designed human brains, THEN the designer of the universe knew (when the human brain was being designed) everything there was to know about the way humans think.
THUS:
28b. The designer of the universe knew (when the human brain was being designed) everything there was to know about the way humans think.
Because we have fixed the confusion about time-frames in Geisler’s argument, the inference here is logically valid. So, we just need to determine whether the premises are true or false. Is (26a) true or false? Geisler has FAILED to show that there is such a thing as “the designer of the universe”, so (26a) might literally be talking about nothing at all. If there is no such being as “the designer of the universe” , then (26a) would be neither true nor false, since the expression “the designer of the universe” has no referent.
Suppose that there were a being that was “the designer of the universe”, would it be reasonable in that case to believe that this being “designed human brains”? There are some good reasons to doubt this.
First, there is good reason to believe that the human brain is the product of random, unthinking forces and processes (i.e. evolution), and thus that even if there were a being that was “the designer of the universe” that being was NOT the designer of the human brain, because the human brain was not the product of ANY intelligent designer.
Second, the universe has been in existence for billions of years, so the designer of the universe, if there ever were such a being, might well no longer exist, and might well have ceased to exist billions of years ago. Since the human brain did not exist until about one million years ago, if there was a designer of the human brain, that being might well only be a few million years old, not old enough to be the designer of the universe. So, even if there was a designer of the universe and a designer of the human brain, they might well have been two different beings who existed in different time-frames, separated by billions of years.
Third, even if there was a designer of the universe, and even if that being still exists today, it might well still be the case that some OTHER intelligent designer produced the design of the human brain. Geisler has provided no reason or argument in support of (26a), so given that there are good reasons to doubt (26a), and no good reason to believe (26a) is true, we ought to reject this premise as probably false.
What about premise (27b)? Is that premise true? There is a good reason to believe this premise to be false. If there was a designer of the human brain, then this designer produced the design of the human brain at least one million years ago, because human brains have been around for at least that long. The structures and functions of the human brain have a very large influence over “the way humans think”, but another significant influence over “the way humans think” is cultural in nature: language, child-rearing, story-telling, education, religion, art, history, music, and philosophy. These various social and cultural factors shape “the way humans think”.
But human languages, cultures, stories, religions, art, history, music, philosophical ideas, are all complex historical phenomena that develop in random and unpredictable ways. It seems impossible for any being, no matter how much knowledge it had of the biology and physiology of the brain, could predict all of the detailed ways in which human thinking would develop and evolve over the span of hundreds of thousands of years.
Predicting the specific behaviour of fairly simple systems of physical objects accurately over hundreds of thousands of years is extremely difficult, so the much more complex and random developments of human cultures and societies (plus the interactions between various human cultures and societies) appears to be an impossible task, even for a being of superhuman intelligence. Thus, there is good reason to doubt that even a being that had a good grasp of the structures and functions of the human brain would be able to anticipate the myriad of random details that would develop in human cultures and societies which would in turn have significant impacts on “the way humans think”. Premise (27b) should be rejected because it is probably false.
Because both of the premises in Geisler’s argument for (28b) are probably false, the argument for (28b) is very probably an UNSOUND argument, so we ought to reject that argument. Furthermore, (28b) is subject to some of the same objections as the premises it is based upon. Like (26a) it might well be talking about NOTHING, since it is questionable whether there is such a being as “the designer of the universe”, and Geisler has FAILED to show that there is such a being. Like (27b), there is the problem of knowing about all of the various details of how human cultures and societies will evolve hundreds of thousands of years BEFORE those developments actually occur. So, we have good reason to believe that (28b) is false, and Geisler has FAILED to provide a good reason to believe that (28b) is true, so we ought to conclude that (28b) is probably false.
Because (28b) is probably false, the argument provided by Geisler in support of premise (30b) is probably an unsound argument. Furthermore, we have good reason to doubt that premise (30b) is true. Premise (30b) is subject to some of the same objections raised against other premises in this argument.
First, the assumption that there is such a being as “the designer of the universe” is highly questionable, and Geisler has provided no good reason to accept this assumption. Second, even if there were such a being as “the designer of the universe” it is quite possible that this being ceased to exist billions of years ago, billions of years before human brains were being designed, and thus it would not be true that “the designer of the universe” had great intelligence at the time the human brain was being designed. Third, there probably is no such thing as the time “when the human brain was being designed” because the human brain is the product of random, unthinking forces and processes (i.e. evolution). Fourth, even if there was such a thing as “the designer of the universe” and there was such a thing as “the designer of the human brain”, these beings might well have been different beings, and thus the intelligence of “the designer of the human brain” would have no relevance for determining the intelligence of “the designer of the universe.”
Geisler has FAILED to provide a good reason to believe that premise (30b) is true, and there are some good reasons to doubt that (30b) is true, so we ought to reject (30b) as probably false. So, Geisler has FAILED to provide a sound argument for this conclusion:
31b. The being that caused the universe to begin to exist had great intelligence (when the human brain was being designed).
CONCLUSION:
Here is the diagram of my final version (Rev.B) of this argument:
I have argued that every premise in Argument #3 of Phase 2 ought to be rejected, except for premise (29):
- Premise (25) is questionable, and because Geisler FAILS to provide any reason whatsoever to believe that (25) is true.
- There are good reasons to doubt (26a), and no good reason to believe (26a) is true, we ought to reject this premise as probably false.
- Premise (27b) should be rejected because it is probably false.
- We have good reason to believe that (28b) is false, and Geisler has FAILED to provide a good reason to believe that (28b) is true, so we ought to conclude that (28b) is probably false.
- Geisler has FAILED to provide a good reason to believe that premise (30b) is true, and there are some good reasons to doubt that (30b) is true, so we ought to reject (30b) as probably false.
I did argue that premise (29a) was clearly and obviously FALSE, because Geisler screwed up the references to time-frames in that premise. But after revising (29) to fix the problem with the mis-matched time-frames between the antecedent and the consequent of that premise, I accepted the revised premise (29b) as a true premise. Other than this one premise, which is true only because I fixed an obvious problem with that premise, every other premise in the argument ought to be rejected.
This argument is a hot steaming pile of dog shit. It is completely unworthy of a professional philosopher who has spent decades teaching and writing about the philosophy of religion and Christian apologetics.
How can Geisler write such crap? I think part of the blame goes to Thomas Aquinas* and to Thomists who follow in the footsteps of Aquinas. As Richard Swinburnes says somewhere, Aquinas’s Five Ways are probably the least successful parts of the philosophical reasoning by Aquinas. But many view the Five Ways as good or plausible arguments for the existence of God, and this widespread delusion creates a very low bar for arguments for the existence of God. The Five Ways should be viewed as examples of HOW NOT TO ARGUE for the existence of God. Because they are often viewed as examples of good arguments for the existence of God, many people are led astray.
Another, perhaps more obvious, problem is that Geisler is preaching to the choir. The audience or readers of Geisler’s books are generally Evangelical Chrstian believers who just want someone in a postion of authority to say “We have very good reasons and arguments to show that God exists, that Jesus is divine, and that the Bible is the Word of God.” These Christian believers are uncritical thinkers, at least when it comes to theology and philosophy, so they will accept any pile of dog shit that Geisler serves them on a china platter. Because Geisler writes for readers who are not skeptical and who are uncritical thinkers, he is intellectually lazy and sloppy, and has no real incentive to do any better.
*I should note that although I think the Five Ways of Aquinas are lousy arguments for the existence of God, I also think that Aquinas never intended the Five Ways to be taken as arguments for the existence of God. Rather, they are merely the initial arguments of a long and complex case for the existence of God that extends far beyond the one page or so where he presents the Five Ways. His case for God is presented in the “Treatise on God” in the First Part of Summa Theologica, specifically the first 26 Questions covered in Summa Theologica, consisting of about 150 pages of interconnected arguments.