Being Logical: A Guide to Good Thinking

by D.Q. McInerny

A dumbed-down logic is not logic at all. Other readers might be put off by what they perceive to be an emphasis upon the obvious. I do, in fact, place a good deal of stress on the obvious in this book, and that is quite deliberate. In logic, as in life, it is the obvious that most often bears emphasizing, because it so easily escapes our notice. If I have belabored certain points, and regularly opted for the explicit over the implicit, it is because I adhere to the time-honored pedagogic principle that it is always safest to assume as little as possible.

We misread a situation because we are skimming it, when what we should be doing is perusing it.

The phrase “to pay attention” is telling. It reminds us that attention costs something. Attention demands an active, energetic response to every situation, to the persons, places, and things that make up the situation. It is impossible to be truly attentive and passive at the same time. Don’t just look, see. Don’t just hear, listen. Train yourself to focus on details. The little things are not to be ignored, for it is just the little things that lead us to the big things.

I establish a fact if I successfully ascertain that there is, for a particular idea I have in mind, a corresponding reality external to my mind. For instance, I have a particular idea in my mind, which I label “cat.” Corresponding to that idea are actually existing things in the extramental world called “cats.” But I could have another idea in my mind, which I label “centaur” but for which no corresponding fact can be found in the extramental world. For all that, the idea of “centaur” is a subjective fact, since it really exists as an idea in my mind.

How do we ensure that our words are adequate to the ideas they seek to convey? The process is essentially the same as the one we follow when confirming the clarity and soundness of our ideas: We must go back to the sources of the ideas. Often we cannot come up with the right word for an idea because we don’t have a firm grasp on the idea itself. Usually, when we clarify the idea by checking it against its source in the objective world, the right word will come to us.

If I said to you “dog” or “cat,” your response would be expectant, waiting to hear more. You would wonder, What about dogs or cats? Through the words I’m speaking, you know the ideas I’m dealing with, but you don’t know what I intend to do with those ideas. I’m simply “saying” the ideas; I’m not saying anything about them. We say something about ideas when we put them together to form statements that can be responded to affirmatively or negatively. Notice that if someone simply says “dog,” there would not be much sense in responding with “That’s true” or “That’s false.”

Don’t assume your audience understands your meaning if you don’t make it explicit. The more complicated the subject matter dealt with, the more important this point is. We

The whole purpose of reasoning, of logic, is to arrive at the truth of things. This is often an arduous task, as truth can sometimes be painfully elusive. But not to pursue truth would be absurd, since it is the only thing that gives meaning to all our endeavors.

They are self-evident. For instance, the first time you read the principle of contradiction, you may have to puzzle over it a moment. But as soon as you see what it is saying, your natural response is, “Of course!”

Another trait of first principles—it follows from their being self-evident—is that they cannot be proven. This means that they are not conclusions that follow from premises; they are not truths dependent upon antecedent truths. This is because first principles represent truths that are absolutely fundamental. They are “first” in the strongest sense of the word. Consider the principle of sufficient reason. I cannot prove that everything that exists must have a cause, nor do I need to, since it is a truth self-evident to me simply by my observing the way the world works. I either see it or I don’t. If the first principles of a science are not seen as self-evident and accepted at face value, the science could not proceed. It would stall right there.

That you might find yourself at times in a situation in which you see no clear alternatives does not mean, objectively considered, that there are no clear alternatives. It simply means that you do not see them. Don’t project your subjective state of uncertainty upon the world at large and claim objective status for it.

The principle of sufficient reason tells us that things don’t just happen. They are caused to happen. We do not know the causes of everything, but we know that everything has a cause. A

But the kind of knowledge that an argument can provide us is more sure than that based upon voices of authority. This is because when we have assimilated a sound argument, we have in effect seen for ourselves that something is true. We know the “whys” behind our knowledge.

The extreme skeptic proclaims baldly that there is no truth. This is obviously a self-contradictory position, for if there is no truth there is no standard by which that very claim can be assessed, and the skeptic’s statement is empty of meaning.

Because the exact whereabouts of something is obviously not known until after it is discovered, we have to keep our minds open beforehand to a variety of possibilities.

The more intense our emotional state, the more difficult it is to think clearly and behave temperately.

7. Argumentation Is Not Quarreling Argument is rational discourse. It is not to be confused with quarreling. The object of argument is to get at the truth. The object of quarreling is to get at other people. There are any number of folk who, though happy to quarrel with you, are either unwilling or unable to argue with you. Do not waste time and energy trying to argue with people who will not or cannot argue.

Common sense looks upon language as principally a means of revealing things, not concealing them, and is suspicious of words that dazzle more than denote.

Established ways of doing things are commendable and worth continuing if they can stand on their own merits. Tradition, taken as a whole, might be regarded as an elaborate set of precedents. The mere fact that “things have always been done that way” is not in and of itself a compelling reason for keeping on doing them that way.

That a majority of the population in a given society holds a particular opinion on a given matter is interesting sociological information, but it has no necessary bearing on the truth or falsity of the matter in question. Majorities can be wrong.

But it is argument, not just the word of the experts, which should be carrying the authoritative weight, and the argument we are presented with here is far from convincing, because it offers us nothing beyond the mere word of the experts. If we are satisfied with only the word of the experts, we are essentially being told: “Don’t ask any questions, just do as we say.”

In the strictest sense, no quality can be quantified, since if quality could be perfectly translated into quantity there would be no basis for the distinction between the two in the first place.

That's just not true. We are still denoting a clear distinction. That does not necessarily eclipse the possibility of gradation of a quality...