Saturday, November 29, 2008

The argument from the psychological relevance of logical laws

IV. Argument from the Psychological Relevance of Logical Laws

My fourth argument concerned the role of logical laws in mental causation. In order for mental causation to be what we ordinarily suppose it to be, it is not only necessary that mental states be causally efficacious in virtue of their content, it is also necessary that the laws of logic be relevant to the production of the conclusion. That is, if we conclude “Socrates is mortal” from “All men are mortal” and “Socrates is a man, then no only must we understand the meanings of those expressions, and these meanings must play a central role in the performance of these inferences, but what Lewis call the ground-and-consequent relationship between the propositions must also play a central role in these rational inferences. We must know that the argument is structured in such a way that in arguments of that form the conclusion always follows from the premises. We do not simply know something that is the case at one moment in time, but we know something that must be true in all moments of time, in every possible world. But how could a physical brain, which stands in physical relations to other objects and whose activities are determined, insofar as they are determined at all, by the laws of physics and not the laws of logic, come to know, not merely that something was true, but could not fail to be true regardless of whatever else is true in the world.We can certainly imagine, for example, a possible world in which the laws of physics are different from the way they are in the actual world. We can imagine, for example, that instead of living in a universe in which dead people tend to stay dead, we find them rising out of their graves on a regular basis on the third day after they are buried. But we cannot imagine a world in which, once we know which cat and which mat, it can possibly be the case that the cat is both on the mat and not on the mat.

Now can we imagine there being a world in which 2 + 2 is really 5 and not 4? I think not.It is one thing to suggest that brains might be able to “track” states of affairs in the physical world. It is another thing to suggest that a physical system can be aware, not only that something is the case, but that it must be the case; that not only it is the case but that it could not fail to be the case. Brain states stand in physical relations to the rest of the world, and are related to that world through cause and effect, responding to changes in the world around us. How can these brain states be knowings of what must be true in all possible worlds?

Consider the difficulty of going from what is to what ought to be in ethics. Many philosophers have agreed that you can pile up the physical truths, and all other descriptive truths from chemistry, biology, psychology, and sociology, as high as you like about, say, the killings of Nicole Brown Simpson and Ronald Goldman, and you could never, by any examination of these, come to the conclusion that these acts we really morally wrong (as opposed to being merely widely disapproved of and criminalized by the legal system). Even the atheist philosopher J. L. Mackie argued that if there were truths of moral necessity, these truths, and our ability to know those truths, are do not fit well into the naturalistic world-view, and if they existed, they would support a theistic world-view. Mackie could and did, of course, deny moral objectivity, but my claim is that objective logical truths present an even more serious problem for naturalism, because the naturalist cannot simply say they don’t exist on pain of undermining the very natural science on which his world-view rests.Arguing that such knowledge is trivial because it merely constitutes the “relations of ideas” and does not tell anything about the world outside our minds seems to me to be an inadequate response. If, for example, the laws of logic are about the relations of ideas, then not only are they about ideas that I have thought already, but also they are true of thoughts I haven’t even had yet. If contradictions can’t be true because this is how my ideas relate to one another, and it is a contingent fact that my ideas relate to one another in this way, then it is impossible to say that they won’t relate differently tomorrow.

Carrier responds somewhat differently. He says:For logical laws are just like physical laws, because physical laws describe the way the universe works, and logical laws describe the way reason works—or, to avoid begging the question, logical laws describe the way a truth-finding machine works, in the very same way that the laws of aerodynamics describe the way a flying-machine works, or the laws of ballistics describe the way guns shoot their targets. The only difference between logical laws and physical laws is that the fact that physical laws describe physics and logical laws describe logic. But that is a difference both trivial and obvious.

What this amounts to, it seems to me, is a denial of the absolute necessity of logic. If the laws of logic just tell us how truth-finding machines work, then if the world were different a truth-finding machine would work differently. I would insist on a critical distinction between the truths of mathematics, which are true regardless of whether anybody thinks them or not, and laws governing how either a person or a computer ought to perform computations. I would ask “What is it about reality that makes one set of computations correct and another set of computations incorrect?”

William Vallicella provides an argument against the claim that the laws of logic are empirical generalizations:
1. The laws of logic are empirical generalizations. (Assumption for reductio).
2. Empirical generalizations, if true, are merely contingently true. (By definition of ‘empirical generalization’: empirical generalizations record what happens to be the case, but might have not been the case.)
3. The laws of logic, if true, are merely contingently true. (1 and 2)
4. If proposition p is contingently true, then it is possible the p be false. (True by definition
5. The laws of logic, if true, are possibly false. (From 3 and 4)
6. LNC is possibly false: there are logically possible worlds in which p & ~p is true.
7. But (6) is absurd (self-contradictory): it amounts to saying that it is logically possible that the very criterion of logical possibility, namely LNC, be false. Therefore 1 is false, and its contradictory, the clam that the laws of logic are not empirical generalizations, is true.

Logic, I maintain, picks out features of reality that must exist in any possible world. We know, and have insight into these realities, and this is what permits us to think. A naturalistic view of the universe, according to which there is nothing in existence that is not in a particular time and a particular place, is hard-pressed to reconcile their theory of the world with the idea that we as humans can access not only what is, but also what must be.


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12 Comments:

At 11/30/2008 06:36:00 AM , Blogger Blue Devil Knight said...

Can you prove the law of noncontradiction without begging the question?

We know, and have insight into these realities, and this is what permits us to think.

What about illogical thought? Isn't that possible? Not just that, isn't it actual? It seems animals use fairly irrational associative processes rather than inferences.

Plus you have the whole paraconsistent logic and liar's paradoxes to deal with. But I don't want to waste a nice vacation dealing with this again, so will just link to what I've said before here and here.

Of particular relevance to this post, I said in the second link (among other places, many times), and Victor hasn't addressed it:

"Someone can consciously go through a bad inference:
If A, then B
Not A.
Therefore, not B.

They can perceive this as a good inference, feel its logical pull very strongly. Let's stipulate that consciously their experience is the same as someone consciously going through a correct inference (e.g., modus ponens).

If this is possible (and I think it is), then it seems the question of logical thought in the argument from reason is really not very strong. The feeling of going through an inference doesn't depend on the soundness of the inference. It's just another conscious experience and can be right or wrong of its target. Hence, the argument from reason doesn't seem to have unique content over and above the argument from qualia to non-naturalism."

 
At 11/30/2008 09:03:00 AM , Blogger Randy said...

Victor,

In order for mental causation to be what we ordinarily suppose it to be, it is not only necessary that mental states be causally efficacious in virtue of their content, ...

Of course, all of this is irrelevant if there is no such thing as mental causation as it is ordinarily understood by philosophers.

I know that is the common assumption made by naturalists and supernaturalists, but I think there are good reasons for not accepting that assumption in the first place.

I find it strange that Lewis, seeing the difference between ground/consequent relationships and causal relatinships would then try to turn that ground/consequent relationship into a pseudo cause/effect relationship.


BDK,
The feeling of going through an inference doesn't depend on the soundness of the inference. It's just another conscious experience and can be right or wrong of its target.

To make a logical inference is to engage in rule-governed bhavior. Whatever feelings one may be having when engaged in that activity are irrelevant.

 
At 11/30/2008 03:44:00 PM , Blogger Blue Devil Knight said...

My point still holds even using withgenstein we can follow crap rules.

 
At 11/30/2008 09:06:00 PM , Blogger Randy said...

BDK,
If you are saying we all can make mistakes and not apply the rules correctly, then of course that is true.

I'm simply pointing out that understanding logical relationships or being able to reason deductively does not require some sort of accompanying qualia.
Nor is understanding a logical relationship a form of inner perception in which we observe these logical relationships in some mental realm.

Understanding is like an ability. And it takes a lot of training and education to master the various forms of logic that humans have developed over the centuries.

 
At 11/30/2008 11:02:00 PM , Blogger Blue Devil Knight said...

Randy: I am sympathetic to the view that there are no qualia that are special to logic. That is directed at Victor's position. I'm pretty sure he wouldn't agree with your view of logic.

My main point is that qua problem in philosophy of mind, the problem of logical thinking doesn't pose any special problems over and above the problems of consciousness and (especially, in my mind) the emergence of propositional thought.

Stepping back from my questions for Victor, I think my original point still stands. What criteria do you use to decide if a particular "ability" is to count as logic? I think it would at the very least involve behavior toward patterns of linguistic strings, which intersentence transitions are endorsed as permissible, obligatory, whatever. This allows for silly logics to be developed (say, within a neandertal species that thinks affirming the consequent is just peachy).

 
At 12/01/2008 06:21:00 AM , Blogger Randy said...

BDK,
What criteria do you use to decide if a particular "ability" is to count as logic?

I wouldn’t say logic is an ability. Understanding is an ability.
There are well established criteria for whether or not a person understands a particular mathematical concept like division or negative numbers. Or whether or not one understands predicate logic or what a logical fallacy is.


I think it would at the very least involve behavior toward patterns of linguistic strings, which intersentence transitions are endorsed as permissible, obligatory, whatever. This allows for silly logics to be developed (say, within a neandertal species that thinks affirming the consequent is just peachy).


Yes, I agree that the capacity for language acquisition would be a necessary pre-condition for the development of a formal system of logic.
And I would agree with your point that other species or alien civilizations could develop logical systems that would appear quite strange to us.

Thanks for the clarification.

 
At 12/01/2008 09:30:00 AM , Anonymous Blip said...

BDK,

I suspect you are missing the point. To take your example inference:

1)If A, then B
2)Not A.
3)Therefore, not B

and another

4)If A, then B
5)A.
6)Therefore, B.

Although some person x may perform the inference from 1) to 3) and think they are performing a modus ponens, and some person y perform the inference from 4)to 6)while thinking the same thing, y would be correct and x would be wrong. This would be because 4)-6) has the property of being a valid inference, which 1-3) lacks. The question then becomes - what accounts for this difference? Hence the positing of logical laws which 1)-3) violates and 4)-6) satisfies.

So it seems that rightness and wrongness of inference pertains to reasoning independent of situation and of what the inferer believes or feels that they are doing.

 
At 12/01/2008 09:34:00 AM , Anonymous Blip said...

Even if some sort of paraconsistent system is true, it would still be a system with encoded laws, and then it would be these laws rather than the laws of classical logic that we mentally engaged with.

 
At 12/01/2008 03:32:00 PM , Blogger Blue Devil Knight said...

Blip-- fine my point is there is nothing philosophy of mind-ish about that metaphysical problem. You make my point for me. See all the stuff I linked to so as not to beat dead horse.

 
At 2/10/2009 02:41:00 PM , Blogger Perezoso said...

2. Empirical generalizations, if true, are merely contingently true.

The usual Mav-P-style deck-stacking. Are the chemical relations and laws outlined by the periodic table "merely" contingently true?

Perhaps the Maverick would like to demonstrate the contingency of say the relation between H20 and a fairly decent sized chunk of potassium. Let's wager on the results--explosion or not. Ouch, Maestro Maverick. (or, say eating food, ingesting H20 to survive--merely contingent??? perhaps a prolonged fast to prove that hypothesis.....)

Providing a "constructive" explanation of the supposed "a priori truths" of logic does not necessarily mean logical knowledge is any less on a sure footing than say the periodic table (or gravity).

We might even agree to a pragmatic analyticity (we call logical form "analytical a priori" as a matter of convenience).

But the knowledge itself, like geometry, did not appear like a miracle in some ancient platonist's head; for that matter , as the early experimentalists realized (Bacon, Hobbes, even Descartes), deductive logic does not really produce much in terms of useful knowledge. Formal logic has some applications (say, programming), but generally somewhat negligible (say in terms of medicine), except in a basic inductive sense, like testing alternative hypotheses.

 
At 10/12/2009 05:14:00 PM , Anonymous Anonymous said...

Victor. (ps. my name is Mark)


if I assume epiphenominalism, and if my brain is composed of 3 levers (A, B and C) and to each correspond (ephiphenomially - as in anomolous Monism) a proposition.

now and each lever can only occupy one of two positions ('up' and 'down' - like a light switch).
now if a lever if 'up' then the person will then be in the state of accepting that proposition.
and conversly if 'down' then the person will not be in the state of acceting that proposition.

now if lever A's proposition (a) is 'All men are Mortal', and if lever B's proposition (b) is 'Socrates is a man', and if lever C's proposition (c) is that 'Syllogisms hold'.
and if the ephiphenominon corresponding to the beleif that (d) 'Socrates is a mortal' is the state in which all 3 levers are 'up'.

in this case there is a direct logical and causitive relation between belifs.
ie. if i believe a, b and c, then i MUST believe d (by logic).

in this case, because physical things obey logical relations (if not 'up' then 'down') and if the content of a beleif is represented in the type of physical attachment (as in my illustration), then physics could (in principle) provide the causal logical relation between beleifs in virtue of their content (as represented in their attachment).

Not sure if this works.

thanks.

BDK: so if there is no qualia attached to logic, then how do you know that something logical is true of the world at all?

Perezoso: evedently all emperical knowledge comes from confidency in the principles of emperical practice, do these not produce usefull knowledge?

 
At 10/12/2009 06:47:00 PM , Anonymous Mark said...

Ok... I've made a dumb mistake.

What I should have said was that: "the ephiphenominon corresponding to the beleif that (d) 'Socrates is a mortal' is triggered by the state in which all 3 levers are 'up'."

But I suppose that presupposes the existance of some kind of mental variable (as to wether or not I believed it)... - and that would probably not be popular with any Materialism.

i suppose i could modify my experiemnt:
a = 'W = X'
b = 'X = Y'
c = 'Y = Z AND logic holds'
d = 'W = Y AND X = Z AND X = Y AND logic holds'

so then: a ^ b ^ c <=> d

Its a bit convoluted but that might work.

 

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