Prologue The Nature of Logic Text from St. Thomas Aquinas 1. There is a twofold operation of the must direct its consideration to the things that belong intellect, as Aristotle says in his book On The Soul. to the three operations of reason we have mentioned. One is the understanding of simple objects, that is, Accordingly, Aristotle treats those [things] belonging the operation by which the intellect apprehends just to the first operation of the intellect, i.e., those the essence of a thing alone; the other is the conceived by simple understanding, in the book operation of composing and dividing. There is also a Categories; those belonging to the second operation, third operation, that of reasoning, by which reason i.e., affirmative and negative enunciation, in the book proceeds from what is known to the investigation of On Interpretation; those belonging to the third things that are unknown. The first of these operation in the book Prior Analytics and the books operations is ordered to the second, for there cannot following it, in which he treats the syllogism be composition and division unless things have absolutely, the different kinds of syllogism, and the already been apprehended simply. The second, in species of argumentation by which reason proceeds turn, is ordered to the third, for clearly we must from one thing to another. And since the three proceed from some known truth to which the operations of reason are ordered to each other, so are intellect assents in order to have certitude about the books: the Categories to On Interpretation and On something not yet known. Interpretation to the Prior Analytics and the books 2. Since logic is called the rational science, it following it.1 Lesson Since logic is one of the most difficult disciplines to master, before we plunge into the subject we should take time to look at it in a general way. We should begin by seeing what we will be studying in logic, why we need to study it, and how we will study it. St. Thomas refers to logic as both the art of reasoning and the rational science. Now every art and every science has a subject what it is about. For example, music makes beautiful sounds, biology looks at living things, and arithmetic studies numbers. Logic is about three things: words, thoughts, and things. Reasoning is a process of organizing our thoughts, but we can do that only by organizing our words. In turn, those words express our thoughts about real things. Perhaps we can best describe the subject of logic by saying that logic is about words insofar as they signify things through our thoughts. Although logic is a difficult subject to study, it is absolutely fundamental to the life of the mind. One way to see the necessity of logic is to compare the mind to the hand. The hand is a universal tool, which can do just about anything, but few things well. My hand by itself is good for grasping, pushing, touching. In an emergency I could use my hands to fight, to rip things apart, to dig a hole. But it is much more convenient to fight with a gun, cut with a knife, and dig with a shovel. It is better to use my hands to make tools, which help me to do these things well. The human mind is much like the hand. By itself it does a pretty good job of thinking about practical matters. No one needs to be a logician to know right from wrong, or to learn how to fix a car. When it deals with the highest questions, however – questions about the soul and God – by itself it rarely thinks well. Like the hand, the mind must make tools for itself that help i it to think well about philosophical and theological questions. It makes words that precisely represent its thoughts, it combines those words into statements, and it combines statements into arguments. These are all tools of the mind. The function of logic is to study these actions in order to make the intellectual tools more easily and without the fear of making mistakes. That is why in another place St. Thomas calls logic the tool of the speculative sciences. Our study of logic will be divided into three parts. First, we will study simple apprehension, that act by which the mind grasps just what something is. Then we will look at composing and dividing, the act by which the mind knows the true and the false. Finally, we will study discursive reasoning, which enables the mind to move from the known to the unknown. Modern philosophy has brought confusion to logic, but we will leave aside the many different “logics” floating around in the modern world. In this course we will study logic in the traditional way, following the doctrine of Aristotle. He is called the father of logic because in his writings he gives an almost complete overview of the subject. The beginning of each lesson in this course, then, will be a passage from one of the ancient philosophers, usually Aristotle, the middle an explanation of that passage, and the end a set of logical exercises. First, let’s examine Plato’s dialogue Meno, one of the earliest considerations of logical themes. 1 Aquinas, Thomas. “Prologue.” Translated by Anthony Andres. Commentary on Aristotle’s On Interpretation. Hillsdale: The Arts of Liberty Project, 2014. ii Lesson One Plato’s Meno Selected Passages translated by Benjamin Jowett Meno. Can you tell me, Socrates, whether virtue delighted to find that I have been mistaken, and that is acquired by teaching or by practice; or if neither by you and Gorgias do really have this knowledge; teaching nor practice, then whether it comes to man although I have been just saying that I have never by nature, or in what other way? found anybody who had. Socrates. O Meno, there was a time when the Men. There will be no difficulty, Socrates, in Thessalians were famous among the other Hellenes answering your question. Let us take first the virtue only for their riches and their riding; but now, if I am of a man – he should know how to administer the not mistaken, they are equally famous for their state, and in the administration of it to benefit his wisdom, especially at Larisa, which is the native city friends and harm his enemies; and he must also be of your friend Aristippus. … How different is our lot! careful not to suffer harm himself. A woman's virtue, my dear Meno. Here at Athens there is a dearth of the if you wish to know about that, may also be easily commodity, and all wisdom seems to have emigrated described: her duty is to order her house, and keep from us to you. … And I myself, Meno, living as I do what is indoors, and obey her husband. Every age, in this region of poverty, am as poor as the rest of the every condition of life, young or old, male or female, world; and I confess with shame that I know literally bond or free, has a different virtue: there are virtues nothing about virtue; and when I do not know the numberless, and no lack of definitions of them; for “what” of anything how can I know its properties? virtue is relative to the actions and ages of each of us How, if I knew nothing at all of Meno, could I tell if in all that we do. And the same may be said of vice, he was fair, or the opposite of fair; rich and noble, or Socrates. the reverse of rich and noble? Do you think that I Soc. How fortunate I am, Meno! When I ask you could? for one virtue, you present me with a swarm of them, Men. No, Indeed. But are you in earnest, which are in your keeping. Suppose that I carry on Socrates, in saying that you do not know what virtue the figure of the swarm, and ask of you, What is the is? And am I to carry back this report of you to nature of the bee? and you answer that there are Thessaly? many kinds of bees, and I reply: But do bees differ as Soc. Not only that, my dear boy, but you may bees, because there are many and different kinds of say further that I have never known of any one else them; or are they not rather to be distinguished by who did, in my judgment. some other quality, as for example beauty, size, or Men. Then you have never met Gorgias when he shape? How would you answer me? was at Athens? Men. I should answer that bees do not differ Soc. Yes, I have. from one another, as bees. Men. And did you not think that he knew? Soc. And if I went on to say: That is what I Soc. I have not a good memory, Meno, and desire to know, Meno; tell me what is the quality in therefore I cannot now tell what I thought of him at which they do not differ, but are all alike; – would the time. And I dare say that he did know, and that you be able to answer? you know what he said: please, therefore, remind me Men. I should. of what he said; or, if you would rather, tell me your Soc. And so of the virtues, however many and own view; for I suspect that you and he think much different they may be, they have all a common nature alike.