Works For Me

When it comes to thinking about human consciousness and reason, people divide, broadly speaking, into two camps: those who see consciousness and reason as primary features of reality, and those who see them as emerging from the activity of suitably configured physical systems (in particular, human brains). For those in the first camp, consciousness is in some important sense prior to the physical brain, and reason apprehends and connects abstracta that have an existence independent of physically instantiated thinkers.

The contrasting view (and the one that I incline toward) is that consciousness arises, in some way that we do not yet understand, from the workings of the brain — which means that before there were any brains in in the world, there was no consciousness — and that reason is a practical affair, a Good Trick that we have learned as a highly effective (and therefore highly adaptive) way of modeling the world so as to predict those aspects of the future that have, over the eons, had some bearing on our reproductive success.

C.S. Lewis considered this physicalist view of reason to be “The Cardinal Difficulty of Naturalism”. Genuine Reason, he argued, must flow according to the logical relations between ground and consequent, while any form of “reason” instantiated as a purely physical system can only proceed according to physical cause and effect. Therefore, he argued, our Reason must cannot rest upon a purely physical foundation, or we wouldn’t be able to trust it.

For Lewis this was a sort of reductio ad absurdum: of course we do consider reason to be trustworthy, and so the only possible basis fit can possibly have is one that transcends the “merely” physical. But as I argued in a post some time ago, there’s another possibility: that our reason actually is quite limited and imperfect, in ways that are hard for us to see — just as we’d expect from a purely practical brain-based system that has been cobbled together over the eons by natural selection. Our trust, in other words, may go too far.

A great deal of clever experimentation and neuro-psychological research has been done since C.S. Lewis died (on November 22nd, 1963, by the way), and the peculiarities, defaults, and curious limitations of human cognition have become far more apparent. Among the more recent ideas about why we reason the way we do is one put forward by Dan Sperber and Hugo Mercier in a paper called Why Do Humans Reason? Arguments for an Argumentative Theory. Their premise? As Jonathan Haidt explains:

“Reasoning was not designed to pursue the truth. Reasoning was designed by evolution to help us win arguments.”

Here’s the abstract:

Reasoning is generally seen as a means to improve knowledge and make better decisions. However, much evidence shows that reasoning often leads to epistemic distortions and poor decisions. This suggests that the function of reasoning should be rethought. Our hypothesis is that the function of reasoning is argumentative. It is to devise and evaluate arguments intended to persuade. Reasoning so conceived is adaptive given the exceptional dependence of humans on communication and their vulnerability to misinformation. A wide range of evidence in the psychology of reasoning and decision making can be reinterpreted and better explained in the light of this hypothesis. Poor performance in standard reasoning tasks is explained by the lack of argumentative context. When the same problems are placed in a proper argumentative setting, people turn out to be skilled arguers. Skilled arguers, however, are not after the truth but after arguments supporting their views. This explains the notorious confirmation bias. This bias is apparent not only when people are actually arguing but also when they are reasoning proactively from the perspective of having to defend their opinions. Reasoning so motivated can distort evaluations and attitudes and allow erroneous beliefs to persist. Proactively used reasoning also favors decisions that are easy to justify but not necessarily better. In all these instances traditionally described as failures or flaws, reasoning does exactly what can be expected of an argumentative device: Look for arguments that support a given conclusion, and, ceteris paribus, favor conclusions for which arguments can be found.

It’s an interesting idea, though my first impression is that it sounds a bit all-or-nothing: while I can easily see how such social factors could have exerted a strong selection pressure, it seems to me that more objective feedback from the real world must have had a major role to play also.

But I’ve only just run across this, and haven’t yet read the paper (or the article linked below), so I can’t say yet if it makes a truly persuasive, well-reasoned argument.

Learn more here.


  1. bob koepp says

    Malcolm – You are certainly(!) right to see this as “a bit all-or-nothing.” When somebody tries to refute an argument by, say, kicking a stone, we tend to be appropriately unimpressed and unpersuaded. And when somebody strings together a number of propositions ending in a purported “conclusion to the argument,” well, if the logical relations between those propositions aren’t of the “right sort” (by which I mean truth-preserving…), again, we tend to be appropriately unimpressed and unpersuaded.

    Posted May 5, 2011 at 12:30 pm | Permalink
  2. Jesse Kaplan says

    Not enough people commented on this to get you to correct at least a couple of glitches. There is a great deal of ground potentially encompassed here and I have not taken the time to consider things. What did occur to me is that C.S. Lewis was apparently arguing on the basis of a difference between cause & effect in nature and cause & effect in logic, or in the abstract. If I understand, what this paper suggests is that arguments that appeal to any thought-system favored by human mentation will be favored. It seems to me this means that both arguments-from-nature and arguments-from-logic will be appealing.

    Maybe I don’t understand what either you or Bob is saying. Bob may be saying the same thing I am saying, only he is using a zen-like metaphor for arguments-from-nature (about kicking a stone) and casting the whole thing in negative terms. Certainly he was more concise!

    Regardless, I fail to see why either this paper about the appeal of polemics, or tricksy little hard-science findings about the mind’s (the brain’s) susceptibility to errors regarding the real world (like optical illusions),undermines Lewis’s point, which may be profound. Lewis has, in effect, demonstrated that consciousness can conceive of objects and principles of relating them which exceed the composition and rules of the real world. I don’t see how showing I make either perceptual/comprehensional errors about the real world or logical/manipulative errors about an abstract world undermines this result. All I can see that this, or you, show is that my thinking is subject to error in general (which itself might be viewed as curious, if mentation arises mechanically from piling up biological building-blocks); even if you can show that it is subject to certain classes of error, like susceptibility to certain sorts of optical illusions, or to appeals to authority or ad hominem arguments, all you are doing is injecting uncertainty about the results of thinking about either real or abstract things. I do not see that you’ve proved physicalism. You would need a meticulously airtight demonstration that the mind is unable to move, so to speak, outside the ambit of the moves permitted by nature, that could be built out of nature’s building-blocks.

    Lewis’s reasoning is actually pretty much like Godel’s. In Godel’s case, his inductions rested on the foundation of his two incompleteness theorems. Those suggest that the last sentence of my last paragraph cannot be the case.

    Posted May 8, 2011 at 3:26 pm | Permalink
  3. Malcolm says

    If you’ll forgive a brief response to such a long comment:

    Nowhere had I ever suggested that I had “proved physicalism”, which is something I would never even attempt to do; I don’t suppose it can be done.

    My point, rather, was that Lewis had failed to refute it.

    Posted May 8, 2011 at 3:54 pm | Permalink
  4. Malcolm says

    Also, I think you are conflating reason and consciousness here; Lewis’s argument was about reason, not consciousness.

    Posted May 8, 2011 at 4:25 pm | Permalink
  5. Malcolm says

    A third point: Godel’s theorem makes a highly technical proof of the incompleteness of formal arithmetic systems. If it says anything at all about human reason, it is that it is not physically implemented in the brain as that sort of formal algorithmic system.

    Posted May 8, 2011 at 7:34 pm | Permalink
  6. howsurprising says

    Genuine Reason, he argued, must flow according to the logical relations between ground and consequent, while any form of “reason” instantiated as a purely physical system can only proceed according to physical cause and effect.

    But some proceedings of cause and effect do so according to reason. This is now obviously true, given that we have theorem provers in propositional logic, first order logic, and modal logics physically instantiated as software on computers (not to mention in the Boolean circuits themselves). But I suppose that Prolog was after Lewis’s time.

    Posted May 8, 2011 at 7:51 pm | Permalink
  7. Jesse Kaplan says

    I wasn’t talking about the incompleteness theorems, but of how Godel privately reasoned from them. In addition, I have various troubles about how you express things, with “physically implemented in the brain” being the most troublesome.

    Posted May 8, 2011 at 9:34 pm | Permalink
  8. Malcolm says

    The proposition that human reason is physically implemented in the brain is exactly what Lewis was trying to refute with his “Cardinal Difficulty” argument, so I guess it was troubling for him, too.

    Posted May 8, 2011 at 10:07 pm | Permalink

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