Ed Babinski on Rational Inference
In a previous post I presented Lewis's description of rational inference.
"Now any concrete train of reasoning involves three elements: Firstly, there is the reception of facts to reason about. These facts are received either from our own senses, or from the report of other minds; that is, either experience or authority supplies us with our material. But each man’s experience is so limited that the second source is the more usual; of every hundred facts upon which to reason, ninety-nine depend on authority. Secondly, there is the direct, simple act of the mind perceiving self-evident truth, as when we see that if A and B both equal C, then they equal each other. This act I call intuition. Thirdly, there is an art or skill of arranging the facts so as to yield a series of such intuitions, which linked together produce, a proof of the truth of the propositions we are considering. This in a geometrical proof each step is seen by intuition, and to fail to see it is to be not a bad geometrician but an idiot. The skill comes in arranging the material into a series of intuitable “steps”. Failure to do this does not mean idiocy, but only lack of ingenuity or invention. Failure to follow it need not mean idiocy, but either inattention or a defect of memory which forbids us to hold all the intuitions together.”
Let's go over what a rational inference is, for C. S. Lewis.
1) Reception of facts to think about.
2) Simple act of the mind perceiving self-evident truth, as when we see that if A and B are equal to C, then A=B.
3) The art or skill of arranging the facts so as to yield a series of such intutions, which, linked together, produce a proof of the conclusion we are reaching.
In his reply to that discussion, Ed Babinski wrote this:
EB: "Rational inferences" are easy to spot at their simplest, like noticing whether or not it is raining outside, or sunny (leaving out the grey areas like a light fog or light sun shower).
VR: This is precisely NOT what Lewis is talking about. These sorts of adjustments do not require the reception of facts to think about, the perception of a self-evident truth, or the arrangement of facts to produce a proof. These are not rational inferences in the sense Lewis is defining.
EB: But even simple living organisms often make distinctions about things in their environment, and react to them in ways that a rational person might consider a rational reaction, even though the organism being examined is far too simple to be considered conscious.
VR: Of course, organisms adjust to their environment. the responses are not rational in the sense we have been discussing. Yes, a rational person (a human, let us say) might think that it is "rational," that is, sensible, for plants to incline toward the sunlight.
EB: At some point however, moving from amoeba to worms to jawless fish to fish to amphibians, reptiles, mammals, monkeys, primitive apes, great apes, and hominids, "rational inferences" appear and the system of the brain/mind seems to recursively feedback information in bigger and bigger chunks, even language-related chunks, making higher level and higher level distinctions and decisions.
VR: By using the term brain/mind are you assuming that the mind, even of an animal, is a purely physical system? The term "brain" is importantly ambiguous, as I have argued previously. It can mean, 'whatever does the cognitive work," it can mean "whatever is located between my ears," or it can mean "a purely physical, that is, mechanistic system that engages in mental processing." If what you mean by "brain" is 3, then whether a brain of that sort is all that is required is precisely the issue in dispute. If you mean by "brain" 1 or 2, then I don't really disagree.
But you will have noticed that rational inference doesn't just require perception of the environment, but the perception of self-evident truths or rules of inference. Things that are not just true here and there, but things that are true because they must be true, in all possible worlds. How to we go from perceiving our environment to preceiving truths that must be true in all environments?
EB: The questions raised by philosophers of various schools is just how much of the increasingly higher levels of distinction-drawing (and decision-making) of organisms (lying along the above spectrum) is "natural" and how much (if any of it) is "supernatural," and at what points during evolution?
VR: Although Lewis used them in Miracles, I dislike using the terms "Natural" and "Supernatural" at this point, at least without definign them. What Lewis means by "supernatural" is just something that "won't fit in" to the mechanistic (non-purposive, non-normative) physical order. It doesn't even mean that you bring God in at this point, all you are doing is saying that the explanation for the event in question cannot be analyzed in non-mental terms. As I've pointed out many times, one can accept that AFR and be an Absolute Idealist, in which case you would be saying that everything is in the final analysis mental and you would not be distinguishing between a "physical" order and a "mental order" at all. You would be saying that nature, appearances to the contrary, is mental in the final analysis. And that is exactly the view that Lewis accepted when he first bought in on the AFR in his discussions with Owen Barfield. In Absolute Idealism, there is no distinction between "Nature" and "Supernature," so I am inclined to resist bringing those terms into the discussion here.
The question I prefer to pose is whether we can explain everything in terms that are in the final analysis non-mental (cranes), or are we stuck with what Dennett calls skyhooks, mind-first explanations that we can't get beyond. I think we need some skyhooks, otherwise we end up denying the reality of rational inference.
But let's make sure we understand what rational inferences are. If you don't like Lewis's definition of rational inference, explain to me what does the work of rational inference without being one in Lewis's sense.