A Challenge to the Argument From Reason 


doctor(logic), who disagrees with me (and other theists) that there is more to the mind than just the physical brain, correctly noted that this post was a version of the Argument From Reason. He responded thus: 

"1) Every system of laws is logical because it relies on non-contradiction and identity. A state of affairs cannot be both predicted and not predicted by a law.

"2) Given this fact, one physical state of affairs has logical implications for other, causally-connected states of affairs.

"3) An evolutionary advantage lies in being able to anticipate physical states of affairs.

"4) Instinctive, non-rational responses can represent very simple relationships between cause and effect (e.g., 'upon seeing an approaching object one should expect an impending collision').

"5) A system capable of analyzing abstract logical relationships has even more advantages than a non-rational one. It can model sophisticated relationships. It can learn and apply those rules within the lifetime of an individual.

"6) Abstract logical analysis can infer laws and relationships in any lawful, physical world. IOW, logic is the same in any world.

"7) Therefore, there is always an evolutionary advantage in being able to model the world with abstract logical reasoning.

"8 ) Therefore, there is a causal connection between logic embedded within physical law and the kind of abstract reasoning ability that would work in any physical world. Through evolution, physical laws can lead to genuine abstract reasoning."

He agreed that his position (including other discussion not quoted here) means that beliefs are identical with physical events, states, interactions--some purely physical condition or other--in the brain, and that inferences from one belief to another are the same as physical interactions, which happen in accordance with physical laws. This is good progress, in my opinion, and an interesting position. Some physicalists (in this context, persons who believe the mind is completely explained by the physical brain) see mental states as epiphenomenal. That is, propositions, beliefs, attitudes, perceptions, etc. are just passengers along for the ride, sitting on top of the physical happenings inside the brain. There are significant weaknesses with that view. It's not doctor(logic)'s position, however. For him, mental states are not riders on physical events, they just are the physical events.

His view summarizes to the belief that evolution prepares the brain to apprehend truth, and that nothing else besides evolution has done this for the brain. Being able to apprehend truth (especially complex or abstract truth) gives organisms a selective advantage, so that those that can manage that feat will have a reproductive advantage, and the skill will become firmly fixed in the population.

I would suggest two serious concerns with this. One has been presented by Alvin Plantinga. It's an extended argument, so I'll offer you just a taste:

"But if naturalism is true, there is no God, and hence no God (or anyone else) overseeing our development and orchestrating the course of our evolution.  And this leads directly to the question whether it is at all likely that our cognitive faculties, given naturalism and given their evolutionary origin, would have developed in such a way as to be reliable, to furnish us with mostly true beliefs."

He quotes the atheistic philosopher Patricia Churchland,

"Boiled down to essentials, a nervous system enables the organism to succeed in the four F's: feeding, fleeing, fighting and reproducing.  The principle chore of nervous systems is to get the body parts where they should be in order that the organism may survive.  . . . .  Improvements in sensorimotor control confer an evolutionary advantage: a fancier style of representing is advantageous so long as it is geared to the organism's way of life and enhances the organism's chances of survival [Churchland's emphasis].  Truth, whatever that is, definitely takes the hindmost."

Does evolution have any interest in truth as such? Why should it? Its "interest"--what is selected for--is just reproductive success. As I said, Plantinga has more to say about it in the paper quoted and also here; this is hardly the complete argument. (One could add that from an Intelligent Design perspective, the whole framework of evolution, and its ability to pull off miracles the likes of this, is suspect; but I recognize that won't matter a hill of beans to a doctor(logic) so I won't press it.)

As Plantinga notes, the miracle of evolution would have to be far more than grand for this to have worked as doctor(logic) says. Suppose for a moment that evolution could have done for the earliest humans what he suggests, in providing us a cognitive advantage for things like hunting, agriculture, storing and cooking food, warfare, etc. What selective advantage in those conditions would have caused evolution to go so far with it? Why did it equip us to work with imaginary numbers (multiples of the square root of -1)? Or physics in 11 dimensions? Or Hamlet, or The Unfinished Symphony (or even The Simpsons)? How much of this did they use on the savanna?

Sure, you could say that these enormous capacities just rose up as tag-alongs as we learned how to throw a rock at a rabbit, or something like that. But isn't evolution supposed to be more conservative than that? Humans expend about 25% of our energy in our brains. We require an extraordinary long time to mature intellectually. These things are extremely costly and disadvantageous. How did evolution know, all those thousands or millions of years ago, that we would need the kind of mental horsepower that could enable us to consider ultimate Theories of Everything, or to write soliloquies and symphonies? Such a degree of mental capacity seems contrary to what evolution ever would have produced. It contradicts the theory.

My second concern has to do with what it might mean for a belief or a proposition to be true, under doctor(logic)'s proposal. If a belief, proposition, or mental state just is a physical state or event within the brain, that means that one physical state is true about something else. This is problematical. It seems doctor(logic) has to smuggle in something other than just physical states or events for this to make sense, or else he runs into the problem of intentionality or aboutness. How is it that one physical thing--a neural state, an electrical event, a chemical interaction, whatever--can be about another? Can the neurons in my brain be about the history of the Peloponnesian wars? Can my brain's electrochemical wiring be about the quadratic formula?

Think carefully now: we know our thoughts can be about such things. But doctor(logic) says our thoughts just are our brain states, and just physical. So it seems he is committed to the position that the physical state of our brain is about other things. I have real trouble seeing how anything physical can have this aboutness.

Again: certainly we know from experience that our thoughts or beliefs can be about such things; but in doctor(logic)'s view, our thoughts and beliefs are very strictly reduced to that which is physical. There is nothing else to them. This runs afoul of what we understand to be true of physical objects and conditions. Just as a rock is not "about" a chair, so a neuron or an electrochemical event cannot be "about" the square root of 16. This blog post is about the topic of mind and brain, but the pattern of white and black you see on the screen, or the electrophysical activity that produced the pattern is not. The difference is that the blog post uses the medium of physical things to convey propositions, which are non-physical; and you, in turn, can interpret those non-physical propositions. (Bill Vallicella has analyzed this problem in some depth, so I refer you to him for more on this.)

There are other problems I won't go into now, like the category difficulties that come when one identifies a physical thing, like brain states and or interactions, with non-physical things, like propositions or beliefs. It also fails to address Lewis's crucial distinction between two kinds of "because." But this has gone on long enough for now. (See apollos.ws for extensive online study resources.)

So it seems there are major difficulties in this view. One has to give up a lot in order to hold on to it. It requires some considerable finagling with the predictions of evolutionary theory, and with our commonsense understanding of aboutness. doctor(logic) must really want quite badly to avoid having to conclude that reality is more than physical.

Related: How Well Does Evolution Explain Human Intelligence?  

Posted: Wed - August 15, 2007 at 07:17 AM           |


© 2004-2007 by Tom Gilson. Permission is granted to quote up to two paragraphs of any blog entry, provided that a link back to the original is included or (in print) the website address is provided. Please email me regarding longer quotes. All other rights reserved.

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