The Argument from Reason

[zippy2006]

C. S. Lewis made famous what is now known as the Argument from Reason. The gist of the argument is that Naturalism is self-defeating because it cannot account for the act of reasoning itself. This is the argument as interpreted by Victor Reppert and Wikipedia:

1. No belief is rationally inferred if it can be fully explained in terms of nonrational causes.
   
2. If naturalism is true, then all beliefs can be fully explained in terms of nonrational causes.
   
3. Therefore, if naturalism is true, then no belief is rationally inferred (from 1 and 2).
   
4. We have good reason to accept naturalism only if it can be rationally inferred from good evidence.
   
5. Therefore, there is not, and cannot be, good reason to accept naturalism.

The Wikipedia article and the sources listed below offer support for the premises and answers to common objections. I will just offer a brief overview of what I take to be the central premise, premise 1.

When someone reasons, we expect that they are able to understand the premises, see the logical connections, and affirm the conclusion based on these principles of validity and soundness. If they are not doing these things then there is no reason to believe that their conclusion is true.

Let's look at an example in which we lack such things. Suppose someone receives brain damage to the extent that the only words they utter are, "It is raining outside." I ask them their name and they answer, "It is raining outside." Do I have reason to believe that it is raining outside, given their assertion? Of course not, but why not? Ultimately, because truth and falsity cannot be fully determined by nonrational causes. Any set of nonrational causes which fully determine a proposition can never yield a reliable means of getting at truth. Yet on Naturalism the statement, "Naturalism is true," is fully determined by nonrational causes. This is because on Naturalism all that exists are material, deterministic, physical realities, to which all "rational" phenomena can be reduced.

If Naturalism were true, then we could never know it, for we could know nothing at all. Our so-called knowledge would be nothing more than the result of nonrational causes. There would be no reason to favor any one proposition over any other, no reason to believe in evolution or creationism over the other, no reason to believe 2+2=4 rather than 5. Yet we do have real knowledge, we can make true judgments, and we do know that 2+2=4. Therefore Naturalism is false.

Sources:

• Wikipedia
• The Argument from Reason and Lewis's Post-Anscombe Revision by Victor Reppert
  
• The Argument from Reason by Victor Reppert
• C. S. Lewis' essay Is Theology Poetry? and book Miracles.

 

[Nihilist Virus]

No belief is rationally inferred if it can be fully explained in terms of nonrational causes.

God's knowledge is not axiomatic, nor even rational in the strict sense--involving ratiocination. It is purely intellectual, like the angels, but even more than the angels, God knows everything that exists exhaustively due to the very fact that he has created everything that exists. He knows it immediately, without reasoning from point A to point B.

So let's see... from this we conclude that no proposition can be rationally inferred unless there exists some entity who has no use for reason.

Back to the drawing board.

 

[zippy2006]

So let's see... from this we conclude that no proposition can be rationally inferred unless there exists some entity who has no use for reason.

Back to the drawing board.

This is just more proof that you have no understanding of what "rational in the strict sense" means, nor concept of the difference between ratiocination and intellection.

 

[Gene Parmesan]

Just because there is a limit to the explanatory power of reasoning, that doesn't prove naturalism to be false. Demonstrate the supernatural if you want to prove naturalism false.

 

[Quid est Veritas?]

A useful corollary to take in account here, in order to better explain the concept, is logic.
For a logical system to be valid, then no false inference must be derived from its premises. If there is a false inference, if it is invalid, then the logic is no longer sound.

Inferences function by a special type of causality, rational insight into relations. For instance, if I assert that A follows from B, so that B is supported by A, this is an inference that can be valid or not. The inference must be true, for it to be valid.
Now Naturalism says A follows from B by the irrational action of matter, by neuronal depolarisation and chemical reactions. This cannot then be asserted to be true, for it was not rationally determined - for A thus not B or thus C might as well have been the result. We cannot determine its actual validity, because we cannot determine whether it is really true. Therefore we cannot determine the soundness of any logical construct when assuming Naturalism. Now Naturalism derives itself from logical reasoning based on empiricism, which it has just rendered impossible to determine the validity of. So Naturalism renders no form of human reasoning sound. The only reason to consider Naturalism at all, was by logical argument, which it has rendered incomplete. Therefore there is no real support for naturalism. Either we then affirm Naturalism, logically unsupported, incomplete and of dubious soundness, and thus say that all logic is moot and with it all our sciences based thereon; or we can make the assertion that Naturalism is therefore logically inconsistent, and maintain all the rest.

 

[jayem]

Now Naturalism says A follows from B by the irrational action of matter,

What does this mean? How does the term "irrational" apply to the behavior of matter?

 

[Chesterton]

What does this mean? How does the term "irrational" apply to the behavior of matter?

I think it means that matter doesn't reason; it doesn't decide things. For example water doesn't reason out whether to flow downhill and then do it, it just does it according to forces which it cannot choose to obey or disobey. It just has to obey, and the result will always be the same. Matter, and its behavior, are irrational.

 

[jayem]

I think it means that matter doesn't reason; it doesn't decide things. For example water doesn't reason out whether to flow downhill and then do it, it just does it according to forces which it cannot choose to obey or disobey. It just has to obey, and the result will always be the same. Matter, and its behavior, are irrational.

To me, that is a very idiosyncratic use of the term "irrational." Which to me means a cognitive process that doesn't conform to reality. Of course, simple matter behaves according to the laws of nature. So in this sense, it always conforms to reality. But simple matter has no cognition. It is more correct to say that it's a non-rational entity.

 

[Quid est Veritas?]

To me, that is a very idiosyncratic use of the term "irrational." Which to me means a cognitive process that doesn't conform to reality. Of course, simple matter behaves according to the laws of nature. So in this sense, it always conforms to reality. But simple matter has no cognition. It is more correct to say that it's a non-rational entity.

If you wish to term it non-rational, go ahead. It does not really alter the argument at all. Rationality is anyway conformation to our reason or logic, not to reality per se.

In its adjectival usage, we can say that something that does not have Rationality is irrational as it fails to be reasoned. Nowhere need the word imply a 'cognitive process' has to be at play. The Oxford dictionary defines irrational as: "not endowed with the power of reason"; for instance. So this is not idiosyncratic at all, but fits the actual dictionary definition of the word.

 

[quatona]

1. No belief is rationally inferred if it can be fully explained in terms of nonrational causes.

I sense a false equivocation already here.
"Rational", as used in the first part of the sentence, uses "rational" as a property of an inference, of a process. Whereas the term "rational/nonrational cause" assumes it to be a property of a thing out there.
Personally, I am only familiar with the first use of "rational", and I cannot really make sense of the idea of a cause being rational. In any case, I fail to see how for a process to have a certain property its cause must have the same property.
It´s almost like saying that walking fast must be caused by Speed.

1. .

   If naturalism is true, then all beliefs can be fully explained in terms of nonrational causes.

Facts and our ability to discern or explain them are two entirely different things.
So no: Everything can be natural ("naturalism can be true")even though we might be unable to (fully) explain everything.

On a more general note, I am not really impressed with arguments against a certain view that appear to affect every other view just the same.

 

[Quid est Veritas?]

I sense a false equivocation already here.
"Rational", as used in the first part of the sentence, uses "rational" as a property of an inference, of a process. Whereas the term "rational/nonrational cause" assumes it to be a property of a thing out there.
Personally, I am only familiar with the first use of "rational", and I cannot really make sense of the idea of a cause being rational. In any case, I fail to see how for a process to have a certain property its cause must have the same property.
It´s almost like saying that walking fast must be caused by Speed.

I agree the wording of the Wikipedia article is not very good. This argument really needs more than a few succinct propositions to be properly made.

What is meant here in the second part of the proposition though, is an efficient cause - that which interact to be responsible for the inference in this case. This is in effect a process to infer the belief must be based on reason, as is implied by the adjective rational that is here negated.

With Rationality though, all steps must be rational or it is not. If a sum has 7 pages of good answers, but a mistake on page two, then everything from page two is wrong. The entirety of the thing needs to be valid for it to be all valid, for it to be rational. This is the logical conception of completeness, for if one strand fails then it all does. It is not that a 'process to have a property' that it cause necessarily has to as well, but when we apply the concept here to a part thereof, this specific concept logically requires its extension to the whole.

Facts and our ability to discern or explain them are two entirely different things.
So no: Everything can be natural ("naturalism can be true")even though we might be unable to (fully) explain everything.

There is a difference between ontological naturalism and methodological naturalism. Facts and our ability to discern them, are of the second. Methodological Naturalism is the attempt to explain and learn from the natural world. Ontological naturalism is merely one interpretive framework thereof, that only this natural world exists in the form of elements and processes and what have you.
Now the fact of the matter is that Ontological Naturalism derives its support from methodological Naturalism, but in the process renders the latter impossible to show such to be valid or sound. Thus it may be true, but it has no way to determine this and in fact negates its own support's validity. It can therefore not be shown to validly supported, so why on earth accept something that renders itself inconsistent and logically incomplete?

 

[zippy2006]

I sense a false equivocation already here.
"Rational", as used in the first part of the sentence, uses "rational" as a property of an inference, of a process. Whereas the term "rational/nonrational cause" assumes it to be a property of a thing out there.
Personally, I am only familiar with the first use of "rational", and I cannot really make sense of the idea of a cause being rational.

Let's just take the very first definition of "rational" from Merriam-Webster:

1a. Having reason or understanding.​

Now let's restate the premise in terms of this definition:

1. No belief is [inferred by reason or understanding] if it can be fully explained in terms of [causes without reason or understanding].​

Thus there is no equivocation. To use the example of my OP that you passed over, the statement made by the person with brain damage is fully explicable in terms of nonrational causes, namely the brain damage received. Since he does not speak the words, "It is raining outside," according to reason or understanding, the statement is not rationally inferred. We know the statement is not rationally inferred because it is fully explained in terms of the brain damage. If it was rationally inferred, then it could not be fully explained in terms of nonrational causes (this is the contrapositive of premise 1). This is a very basic commonsensical principle that is used in everyday life. For example, statements made in one's sleep and acts done in states of insanity are not taken to be rational acts.

In any case, I fail to see how for a process to have a certain property its cause must have the same property.
It´s almost like saying that walking fast must be caused by Speed.

You are claiming that the argument commits something like the fallacy of composition with respect to the set of causes and the effect. That is to say, even if no cause has property X, it does not follow that the effect of those causes does not have property X. But like the fallacy of composition, this is not universally true. For example, if I construct a wall out of bricks that are not red, I will never produce a wall that is red.

Rational inference is another case where the fallacy does not obtain. If a set of nonrational causes come together to create some belief, that belief cannot have been rationally inferred. Rational inference requires reason, understanding, and an inferred conclusion based on the laws of logic and the premises at hand. Nonrational causes preclude such things. It cannot be the case that the statement, "It is raining outside," is fully explained by brain damage and at the same time is rationally inferred by the subject.

Facts and our ability to discern or explain them are two entirely different things.
So no: Everything can be natural ("naturalism can be true")even though we might be unable to (fully) explain everything.

You are confusing principle with practice. The consequent of the premise is, "All beliefs can be fully explained in terms of nonrational causes." For the Naturalist, this must be true. The meaning of the consequent is, "All beliefs can in principle be fully explained...," not, "All beliefs can at present be fully explained..." The relevant negation is therefore, "Some beliefs cannot--even in principle--be fully explained in terms of nonrational causes." That is, some rational causes must be introduced to explain some beliefs. The Naturalist, believing that beliefs and reasoning are fully explicable by material and physical causes, emphatically rejects this negation.

On a more general note, I am not really impressed with arguments against a certain view that appear to affect every other view just the same.

Tu quoque? You haven't said enough to make me believe you. Lewis believes Naturalism is false because not all beliefs can be fully explained in terms of nonrational causes, and the argument is evidence for such a view.

Suppose that reason, by way of an intelligent creator, was a fundamental cause of creation. Suppose the creator endowed certain creatures with the ability to access the same reason that acted as a blueprint for all that exists. In that case rational inference is not the problematic result of nonrational causes, but rather the reflection of eternal reason itself. In that case there is an enormous abyss between apes and humans. The tu quoque, while technically fallacious, still fails.

Galileo once said, "Mathematics is the language with which God wrote the universe." Lewis might have substituted "mathematics" with "rationality." In any case, they are all footnotes to the first words of John's gospel:

In the beginning was the logos, and the logos was with God, and the logos was God. He was in the beginning with God; all things were made through him, and without him was not anything made that was made.​

 

[quatona]

Sorry, not enough time to deal with sophism exhaustively. Have fun!

 

[jayem]

Lewis believes Naturalism is false because not all beliefs can be fully explained in terms of nonrational causes, and the argument is evidence for such a view.

So--if I understand--this is what Lewis is saying: He can't comprehend how purely natural processes could produce cognitive organisms having the powers of reason and logic. So it must result from some supernatural entity. If you think this a compelling argument, that's fine. Seems to me, it's just a restatement of the argument from ignorance. Human beings have always concocted gods or spirits to explain weather, diseases, floods, earthquakes, the motion of the sun, moon, and stars, and many other things which were not understood. Yet as our understanding has improved, we know that all of these are perfectly natural phenomena. In the entire history of human knowledge, a supernatural explanation has never been valid for anything. So--by simple induction--why should I accept a supernatural causation for those things I still don't fully understand?

And I can use inductive (or deductive) reasoning because the neural circuitry in my brain evolved those capabilities. It also evolved the ability to use language so that I can communicate complex ideas with my fellow humans. Just like evolution gave me a gastrointestinal tract that can digest both animal and plant matter. And I have bipedal posture that frees my upper extremities for tasks other than locomotion. All of these functions evolved. They were favored by natural selection because they enable us to adapt and survive in changing environments and better reproduce our species. Our brains are no exception. They evolved by natural processes just like all of our other organs.

 

[zippy2006]

So--if I understand--this is what Lewis is saying: He can't comprehend how purely natural processes could produce cognitive organisms having the powers of reason and logic.

Sort of. It would be more accurate to say that he believes Naturalism invalidates itself, and the argument in the OP proves this.

And I can use inductive (or deductive) reasoning because the neural circuitry in my brain evolved those capabilities.

If you really believe that some of your beliefs are true in virtue of rational inference, then you cannot consistently hold Naturalism. The Naturalist who believes they have rationally inferred the belief, "Naturalism is true," is just being inconsistent. They are failing to comprehend the logical conclusion of their premises, and thus holding to a conclusion that contradicts their premises. Either drop Naturalism or drop rational inference. You can't have both.

 

[quatona]

The Naturalist who believes they have rationally inferred the belief, "Naturalism is true," is just being inconsistent.

I´m not sure there´s any naturalists who believes they have "rationally inferred" this belief - by your definition of "rational inference" (i.e. when they say "rational inference" they don´t mean what you mean). So it´s not like they are inconsistent, it´s more like their belief and the idea and criteria of "rational inference" that you superimpose on them are irreconcilable.

Either drop Naturalism or drop rational inference. You can't have both.

I have never subscribed to the concept of "rational inference" as postulated by Lewis etc., to begin with. And I am not even a naturalist.

 

[Quid est Veritas?]

I´m not sure there´s any naturalists who believes they have "rationally inferred" this belief - by your definition of "rational inference" (i.e. when they say "rational inference" they don´t mean what you mean). So it´s not like they are inconsistent, it´s more like their belief and the idea and criteria of "rational inference" that you superimpose on them are irreconcilable.

I have never subscribed to the concept of "rational inference" as postulated by Lewis etc., to begin with. And I am not even a naturalist.

So in your opinion, no Naturalist holds to Logic as it has been understood for millenia? Nor do they believe they reason their arguments? They disagree that we can make conclusions that are valid based on our observations? Okay then. If this is the case, then this thread belongs in the Debate non-Christian Religions Forum and clearly Naturalism is the most unscientific thought paradigm in existence.

If I had been a Naturalist, I would have been highly offended by your characterisation, especcially seeing that you deny Naturalism yourself.

 

[quatona]

So in your opinion, no Naturalist holds to Logic as it has been understood for millenia?

It´s more like in my opinion logic has always been understood to be a process of getting from a premise to a conclusion.

Nor do they believe they reason their arguments?

Sure they do.

They disagree that we can make conclusions that are valid based on our observations?

No.
I think that any concept of epistemological validity that implicitly or explicitly postulates or claims the absence of axioms is intellectually dishonest.

If I had been a Naturalist, I would have been highly offended by your characterisation, especcially seeing that you deny Naturalism yourself.

That´s probably because you didn´t read carefully what I actually said (I can say that because your above three attempts of paraphrasing what I said went completely wrong).

 

[Quid est Veritas?]

It´s more like in my opinion logic has always been understood to be a process of getting from a premise to a conclusion.

I take it you have never read Aristotle.

That´s probably because you didn´t read carefully what I actually said (I can say that because your above three attempts of paraphrasing what I said went completely wrong).

I disagree, but that's fine. If you can refuse to answer, because you presume sophistry, so can I when the real McCoy is presented me; as you have, of course, not explained how they do see 'rational inference' then.

 

[quatona]

I disagree, but that's fine. If you can refuse to answer because you presume sophistry, so can I when the real McCoy is presented me; as you have of course, not explained how they do see 'rational inference' then.

Sure you can.
And indeed it would be better to ask a naturalist rather than me about their tenets.
I can only tell you what I understand "(rational) inference" to mean, and in this understanding rational inference and naturalism are perfectly reconcilable.

On an more general note, I find it quite unfortunate how you permanently change the keyterms ("rational", "reason", "rational inference", and now even "logic" - and in his recent post to me Zippy even introduced "common sense" ).

Bottom line: Axiomless epistemology can not be had. Thus, pointing out that a certain view involves axioms is just stating the obvious and inevitable.