Claudio
Gutierrez 
Translated from Spanish by Inés Gutiérrez
Claudio
Gutierrez
The beautiful words on education once spoken by Cardinal Newman can also be applied to logic, as we understand it in this book:
It is what gives man a clear vision of his own opinions and judgments, truth in their development, eloquence in their expression, and force in their defense. It teaches him to see things as they are, to come to the point, to wind a hank of thought, to discover what is fallacious, and discard what does not fit the case. It prepares him to fulfill any job with distinction and master any subject with ease.
Learning logic in this sense is learning the appropriate use of language. Language is a fine, delicate, and even dangerous instrument. We must get to know it with the same caution we experience in handling a precision machine. Only in this manner will we be able to extract the immense utility it contains. The correct use of language is, above all, reading and listening intelligently and with a critical spirit. Furthermore, it is expressing oneself with the intellectual certainty of one who knows his statements are clear and do not contradict each other.
This course has to do with language, but it is not a language course, for example, the English language. We will not be speaking about grammar or vocabulary as such, although we will assume the student knows his grammar and commands a respectable vocabulary. It is not the language in itself, but its practical use, what interests us. The difference between an English course and a course on logic will become clearer as we advance further. The student will discover by himself the differences and similarities between the two kinds of courses.
Our course seeks to encourage clarity and agility of mind in the student, and promote intellectual skills. When these are lacking, the strange phenomenon arises of a person who sees in what he reads or understands in what he hears something very different from the meaning intended by the author. Someone not capable of grasping in a text or speech what the author put there, and only that, is far from being able to cope with the implications of what is written or said.
We usually use the term “logical” in the sense of “reasonable”. Logical is what seems to be sustainable, what one can assert without fear of being exposed to rebuttal or even ridicule. In this course, however, we will give the word a more limited and technical meaning. We will consider something as logical to the extent it has to do with clearness and accuracy of mind, or correctness and surety of assertion. We will posit logic as the discipline dealing with language analysis, regarding its sense and its structure, and with the understanding of the methods of inference we use. All this will also become clearer as we move along.
The art of logic can be acquired without ever having studied it, simply by reflection, by trial and error, or by imitation of those who dominate the art. If the formal learning of logic helps us to absorb what we read more intelligently, it is also true that intelligent reading can teach us much logic. In any case, in this as in everything else, much learning time can be saved by systematically studying an art, averting the possibility of some things being learned wrongly or not at all. That is why it is convenient to take a course on logic at some point in life, the sooner the better.
Logic is said to be the study of the laws of thought. But how we think is also of interest to psychology, a different science from logic altogether. Logic concerns itself with clearness and correctness of thought, not with how it originates in the mind or what part it plays in an individual’s personality. We can say that psychology concerns itself with thought inasmuch as it is a specific function of human life. Logic, on the other hand, is interested only in what is common in thought, independently of who has it in his or her mind. Furthermore, not every thought is of interest to logic. It is not interested, for instance, in imaginative thought or in “day dreaming”. It is solely interested in thoughts in the form of propositions, that is, affirmations or negations of facts, or in those under the form of arguments, that is, transitions from the truth of some propositions to the truth of other propositions. For example, logic is not interested –but psychology is– in how a scientist arrives at a great idea. Instead, logic is very interested in knowing if the idea is consistent, or to what extent can we consider it to be true, and why. These things are not the concern of psychologists as such.
Logic is much applied in discussions or polemics between parties defending different points of view. It is extremely important for us to clearly establish by analysis which are the respective theses or issues being defended or attacked. But we have to be realistic and accept that not all intellectual confrontations can be solved by the application of logic. In many cases, it will only be possible for us to demonstrate our theses through arduous and complicated experimental research. At other times, the disagreement between the parties will not be about facts but it will rather be a disagreement of attitude about the same facts. A conservative and a progressivist can coincide in the description of an event, but the conservative complain about it, while the progressivist rejoices. Confronted with the same situation, the former can say: “Mores are corrupted”, while the latter says: “Mores are liberated”. A conflict such as this cannot be solved by research or logical analysis. It can only be solved, if at all, by means of persuasion, which is not a matter of logic but of a parallel discipline, rhetoric. The act of persuading others consists of trying to move their emotions so that they will be better disposed to a change of perspective or a recalibration of their scale of values. In such cases logic can still be of some help, for instance, by clarifying the consequences of each position; but it can never say the last word.
We will divide our course into two large sections. The first one is language analysis. The second is the study of the methods of thought. The first deals with the conceptual clarity and accuracy to which logic contributes. The second deals with inferential correction, that is, the transition from the truth of some propositions to the truth of other propositions. Language analysis begins by distinguishing the different functions of words and phrases: we must separate the expressive or imperative phrases from the informative phrases, the latter being the primary concern of logic. Furthermore, statements and words can also perform emotional functions, manifest the intimate world of the individual, rather than representing the state of the external universe. These three different roles of words have to be distinguished. We call this kind of analysis, analysis of sense. In addition we have to deal with an analysis of structure. This type of analysis concentrates on clarifying the informative phrases in order to understand the manner in which they are built and how they can be useful to describe our surrounding universe. Finally, we must study how the human mind moves from the truth of certain propositions to the truth of others; that is to say, how the valid processes of inference are carried out. Here we will differentiate between two types of inference: secure inference, or deduction, and probable inference, or induction. We will try to clarify these general concepts a bit more in the next chapter.