Does reason matter? (1)


What is reason? Is it good, bad, or neutral? Is being reasonable an important part of what makes a person virtuous? Does reason help us find Truth or just truths? Though the word “reason” is used in many ways in English, I can think of three common meanings that come up in the context of discussions about philosophy and religion. To get clear on what these three definitions are, think about these statements:

“You don’t have to be reasonable to find the truth.”

“Reason is subjective and not a reliable guide to finding the truth.”

“A person can be totally reasonable but also completely insane, lost in dangerous delusions.”

In the past I thought that such expressions were only common among people who do not study serious philosophy. I was irritated on many occasions when people said similar things, and would have considered such folk to be “irrational”. My reactions included the following:

“It’s bad to be unreasonable!”

“If you don’t care about reason, then you don’t care about distinguishing what is true from what is false; and if you don’t care about that, then you can’t find truth.”

“Reason is essential for living a good life; without it, you will believe just anything and make unwise decisions.”

Who is right here? Let’s try and unravel the confusion by distinguishing different definitions of reason.

Reason (1): Thought processes that are aimed at getting information.
By this definition, reason is a process that the mind or intellect goes through when presented with information about the world (whether that information comes from our perception, imagination, introspection, or something else). The mind sorts through this information, trying to organize it and discern true from false, reality from appearance, blue from green, etc. Reason in this sense is subjective because it is something that a person (subject) does. And reason in this sense is also subjective because it has no guarantee of landing a person with knowledge of the truth. Just because you think something doesn’t mean it is so; just because your mind (imagination, mental sorting processes, or whatever) suggests something doesn’t mean it is so. This is how we use the word “reason” when we say “The lawyer reasoned about how to defend his client.”

Reason (2): Deductive and inductive inferences.
Another way that we commonly speak of reason is in terms of formal arguments. An argument is a piece of reasoning. In order to work, it must follow rules about form and content. Arguments have premises that point to or indicate a conclusion. In a deductive argument, the premises logically imply the conclusion; in other words, if the premises are true, the conclusion has to be true. For example:

P1. If something is a mammal it is an animal.
P2. Toby the dog is a mammal.
C. Therefore, Toby the dog is an animal.

An inductive argument begins with a premise which appeals to several observed specific examples. These examples are grouped into general categories to draw a general conclusion. If the premises are true, they make the conclusion likely. For example:

P1. Out of each of the fifty times I have picked up a pencil and dropped it, all 50 of those times is a time the pencil has fallen.
C. Therefore, it is probably true that whenever I pick up a pencil and drop it, it will fall.

We can figure out from past experiences that it is very likely that the pencil will always fall when dropped; but it is not certain that this will happen.

Now induction and deduction are great as far as they go. Deductive arguments can give us certainty that a conclusion follows from its premises, and inductive arguments can lead us to draw conclusions that are very likely to be true. But each of them has a problem. If a deductive argument is valid, it only gives certainty that the conclusion follows from the premises. But it doesn’t tell us whether the premises are true (and thus whether or not the conclusion is true). So deduction does not, by itself, supply us with true premises. Inductive arguments fail to grant certainty because their premises only make their conclusions likely.

Furthermore, there are all kinds of fallacies that are committed in inductive and deductive arguments. But there are no rules about how to figure out when one of these fallacies has been committed. Take the fallacy of hasty generalization. This happens when an inductive argument draws a conclusion without enough concrete examples of evidence to adequately support that conclusion. For instance, if I have seen 300 cats during my lifetime, and every cat I saw had a tail, I might come to the general conclusion “all cats have tails”. Would this be reasonable? You might say “you should have consulted the scientific literature, or a children’s book on animals, and learned that some cats are tailless.” But what if I have also read 20 science books and 30 children’s books on animals and they didn’t mention cats without tails? How much examination of a subject matter is enough?

This is complicated even more if we are making generalizations about societies. A common argument against some forms of Marxism is that each attempt to achieve it’s ideal economic and political entity have failed; therefore, probably all attempts will fail. But it could easily be retorted: it hasn’t actually been tried, because everyone who claims to try has grasped at power and created a new elite; if someone actually tried it, perhaps it could succeed. Are we making a hasty generalization if we say, based on our available evidence, that a Marxist or near-Marxist “state” cannot be achieved? Perhaps. But maybe our available samples of attempted Marxist “states” are not examples at all, or are not numerous enough to justify the conclusion that it is impossible. It is difficult to say that there is a “rule” about how much searching for examples is enough to justify drawing a general conclusion.

It hardly seems like reason in this second sense is a sure guide to knowledge of reality, or to a virtuous life. At the very least it is safe to say that it is not enough by itself. But is there another sense in which reason can give us a sure, steady guide to how to know about the world? Is there a sense in which we should follow reason, always, and at all costs, in the effort to become virtuous? In the next post, I will try to answer this question.


7 Responses to “Does reason matter? (1)”

  1. Iordanis Says:

    I think another looming question, especially with regards to deductive reasoning and formal logic, is how is it that we are sure that our rules of inference are actually truth preserving. For example, on what grounds can we justify modus ponens. If we say that this (or any other rule of inference) seems to always yield true conclusions then deduction is actually a sub discipline of induction. If we say we can’t imagine it yielding false conclusion, then it seems that deduction does not belong to the category reason-2 (as you have labeled them) and really belongs with reason-1

  2. Andrea Elizabeth Says:

    I believe there’s a balance between being too afraid to use reason for fear of the eventual discovery of a tailless cat and overconfidence in ones own experience. People are less confident now as assumptions get proven wrong, but if it paralyzes them, seems like they’ve lost a vital function.

  3. MG Says:


    Regarding the truth-preserving status of rules of deductive logic, I would tentatively say that at least many of them are analytic propositions. We are non-inferrentially justified in accepting them because once we understand them, we know that they are true and logically necessary. This does not require induction, thought experiment, and perhaps it does not even require intuition (though perhaps in some special sense intuition is involved). Whatcha think?

    • Iordanis Says:

      Your statement, “We are non-inferrentially justified in accepting them because once we understand them, we know that they are true and logically necessary.” seems like a tautology ‘once we understand… we know…’ I think we’re simply restating the Problem of the Criterion. We must beg the question…

      • MG Says:


        I don’t think so. I can understand the proposition “there are exactly ten trillion galaxies in this universe” without knowing whether it is true or false. Thus, to understand a proposition is not the same as knowing that the proposition is true. (We might speak of “knowing what a proposition means” and “understanding that a proposition is true”; but by this we really mean “understanding a proposition” and “knowing that a proposition is true” respectively.)

        So the distinction between understanding and knowing seems like it can be maintained. And thus it is not tautological to claim that there are some propositions such that to understand the meaning of that proposition will give knowledge that the proposition is true or false.

      • MG Says:

        Also, the problem of the criteria is in some sense pre-dialectical. Question-begging does not enter into it, at least not in the manner of normal question-begging in the context of arguments.

  4. MG Says:


    Agreed; though if by appealing to experience we mean “science”, then I would classify that as an extension of induction. I think that nowadays many of the intellectual elite have a naive confidence in experience/science/inductive reasoning. They assume that all the conclusions we form that are not directly based on scientific evidence are automatically suspect. This is ironic, in my eyes, because we can only know that inductive principles work by the use of our intuition. In a different age, the elite tended to have the opposite error of trusting in rationality (of a sort) too much, in a way that conflicted with experience.

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