Lorenzelli Library now features 500 volumes!

With many English works in addition to the Latin.  We plan to add 5 new, out-of-print works of Scholastic philosophy (and, yes, even some theology) every week.   The goal is to create the single largest library—online and off—of Scholastic sciences and arts. 

Please note that the library location HAS CHANGED, and we now use online flipbook technology for ease of reading.  Full members of the ISS can access the library at www.SocietyofScholastics.org/members.   Old passwords HAVE NOT carried over to the new library; so if you want to sign up again, please send us an email: TheSchoolmen@societyofscholastics.org

New books added to the Lorenzelli Library

Full members can log in at www.societyofscholastics.org/library and read the latest additions, including:

  • All eight volumes of Urraburu’s philosophy course from the Gregorian University;
  • All five volumes of Rosselli’s excellent Summa Philosophica;
  • Tongiorgi’s in depth logical treatise;
  • A great two-volume English introduction to modern Thomistic philosophy by R.P. Phillips;
  • Pesch’s two volume treatment of natural philosophy;
  • The commentaries on De Anima and De Physica by Aquarius and Franciscus De Sylvestris Ferrariensis;
  • Suarez’s excellent political treatise, ‘De Legibus’ ;
  • And many other great works by De Lugo, Costa-Rossetti, Banez, and Jouin.

What we’re doing in Material Logic

Jumping into Metaphysics for a short while, we’ve clarified the object of Logic by discussing the difference between real being (i.e., ens reale or mind-independent being) and being of the reason (i.e., ens rationis or mind-dependent being).  We saw that beings of the reason, which are understood precisely because of their inability to exist, are of two kinds depending on their opposition to real existence: negation and relation.  We saw that some relations of reason have foundations in something insofar as that thing exists in reality, while some relations of reason have foundations in something insofar as that thing exists in intellectual knowledge: these latter we call second intentions, and it is these that we are concerned with in Logic.  We said that these second intentions vary according to the different ways that a subject can be known.  When it is known by simple apprehension we have such second intentions as definition, term, extension, etc.  When it is known by judgment we have such intentions as being the subject of predication, supposition, contradiction, perseity, etc.  When it is known by reasoning we have such second intentions as induction and deduction, syllogistic moods and figures, demonstration, dialectics, etc.    

With the goal of explaining the various kinds of certitude that a valid syllogism can present, we are ultimately aiming at demonstration; this means that we must begin by looking at those various second intension or logical relations which are necessary in order to construct a demonstrative syllogism.  Since definition is always the middle term in demonstration, we must first examine definition; since definition isn’t possible without understanding genus, species, difference, property, and accident we must begin with the relations of the predicables; and since the predicables are the five possible logical relations (second intentions) of the logical universal, we will first begin by examining the logical universal and the ways it can be related to its logical inferiors.  Once we’ve examined the perfect process of reason, demonstration, we will examine the various ways that it can fall short of this: scil., dialectics and the lesser degrees of certitude.

What we’re doing in Formal Logic

After an introduction which covered the nature and branches of philosophy—discussing how philosophy became wrongly divorced from science in modern thought—we talked about the nature of Logic, its division into natural and artificial, the doctrine of Logic and the art of Logic, and the division of the one science of Logic into Formal and Material studies.  We said that things in reality have certain properties which characterize them, but as they exist in the intellect they take on new properties which can be utilized to bring out new knowledge.  We saw that a perfect process of reasoning validly concludes to new knowledge but also that such a conclusion can be of varying grades of certitude. We talked about how Formal Logic is interested in those logical properties which are necessary to correctly bring out conclusions from our old knowledge, while Material Logic is interested in those logical properties (e.g., genus, species, property, definition, division, demonstration, probability, etc.) which are responsible for different degrees of certitude in our valid reasoning.  We saw that while Logic and its arguments appeal only to the intellect by means of intellectual evidence—some arguments leading to absolutely certain knowledge in demonstration, some leading to various degrees of probability in dialectics—there are also attempts in human discourse to force one to accept a conclusion by appealing, not only to the intellect, but to the will and the emotions: this is the domain of Rhetoric and Politics which depend upon the study of Psychology because they are concerned with the interaction between intellect, will, and sensitive appetites. 

We’ve made a distinction between the operations of the intellect, the products of those operations, and the signs of those products.  Beginning with simple apprehension, we’ve examined the nature of this operation and its product, the concept.  We saw the first two logical properties that every nature acquired when it is conceived by the mind: comprehensive content and extension.  Following our general procedure of definition then division, now that we’ve covered the concept in general, we will divide the concept into its various kinds according to its various logical relationships.

Sample of “The Natural Superiority of Traditional Worship”

The March 20th lecture on “The Natural Superiority of Traditional Worship” has generated a lot of positive comment.

In order to give a wider audience a sense of the lecture we have included a free download of a section of the lecture here

The full lecture can be purchased here. Hit the button next to the lecture date (20th March) to purchase the lecture and the full mp3 file will be sent to you.

Our Prayer Request Block

In these tough economic times it is not always possible for members to support the Society financially. We would, however, ask you to support us with your prayers.

For that reason we have set up a prayer request block with the following categories: Masses, rosaries, Holy hours and other prayers.

If you would like to send me the totals of your masses and prayers on a weekly or monthly basis, I will post the totals in the block.
Christopher’s e-mail

From the Director’s Inbox

“Is the explicit use of syllogisms the only way to argue or to write? For isn’t it true that everyone who makes an argument, whether he be a philosophic writer or not, employs syllogisms, although not necessarily explicitly, since of course this is the way the reasoning process works, necessarily so?”

Let’s deal with the questions one by one.

1) Is the explicit use of a syllogism the only way to argue?

We need to begin by making a distinction between the intellectual process of reasoning and the external sign of reasoning. A syllogism, in a wide sense, is the extra-mental sign of this reasoning process (syllogism in the strict sense refers only to the sign of deductive reasoning, but I prefer to use the name syllogism as applying to all kinds of reasoning: deductive, inductive, and expository); a sign whereby what’s taking place on the intellectual level in the act of reasoning can be communicated to someone else. An explicit syllogism is one which follows the syllogistic procedure of two antecedent propositions called the premises (one being ‘major’ and the other ‘minor) and one consequent proposition called the conclusion (e.g., Every A is B; but every B is C; therefore, every A is C). Let’s take argumentation to mean the attempt to cause the same reasoning process in the minds of others—to cause them to see why a proposition is true so that they understand it to be true, not merely to believe a proposition.

Now, the internal process of reasoning always proceeds by comparing two previous judgments to each other so that a third and previously unknown judgment is caused by their appropriate arrangement—this is always required for reasoning to take place for it is in this causation of a new judgment that reasoning consists. The purpose of argument is to cause a reasoning process in the mind of another so that the conclusion is brought about in his intellect. This means that we must cause the two previous judgments in the mind of the other and cause their appropriate arrangement so that the new judgment—the conclusion—is clearly perceived. Whatever method is suitable to bring about this reasoning process in another’s mind will be a sufficient form of argument. Now, the syllogism is the clearest representation of this reasoning process—it contains nothing but the two previous judgments (uniting previously known concepts) arranged in such a way as to bring out the evidence of the conclusion. And being the clearest representation, it is the easiest to see the exact process of reasoning which is being presented and to identify any mistakes.

However, this does not mean that we must always use the syllogism when arguing with others. First, as I said, any method suitable to causing the previous judgments and their appropriate arrangement in the mind of another for the sake of the conclusion is a sufficient form of argument. But sometimes one of the previous judgments is so obvious to the other person that it need not be spoken. Hence, sometimes we can leave one of the premises out of an argument as when I say, ‘an isosceles is a triangle; therefore it has three sides’, where the premise ‘all triangles have three sides’ is sufficiently known to the hearer that I need not state it. Again, sometimes merely presenting the two premises of an argument is sufficient to bring about the conclusion without having explicitly to state it. Hence, sometimes we can leave out the conclusion of an argument, as when I say ‘man is an animal and all animals require nourishment’, where the conclusion ‘therefore, man requires nourishment’ is usually sufficiently seen to follow from the premises. Any form of argument where parts of the syllogism are left out (and hence doesn’t signify every element of the reasoning process), but is still sufficient to cause that reasoning process in another (because what is unspoken is still otherwise discernible) is called an enthymeme, an implicit syllogism, or an abbreviated syllogism (though I use the word enthymeme differently than did Aristotle). In order to cause reasoning in the mind of another—the purpose of argument—the premises and the conclusion must be represented to that mind. If this can be done without explicitly stating those things, then an implicit syllogism is all that is necessary for argument. Indeed, to clearly state every part of a syllogism when it isn’t necessary becomes tedious and makes communication needlessly difficult.

Furthermore, though arranging the syllogism into major premise, then minor premise, then conclusion is the simplest representation of reasoning, it is not always necessary to do this in order to cause the other person to perceive these three propositions. Hence, they need not always be arranged in the explicit form of a syllogism, as when I say ‘man is risible because he is rational and all rational things are risible’, where ‘man is risible’ is the conclusion even though it comes first. When a syllogism is clearly arranged in major-minor-conclusion order it’s called strictly logical form. Otherwise it is called loosely logical form. And we can use both loose forms of argument and enthymemes together, as when I say ‘man is risible because he is rational’, where again the conclusion comes first but, in addition, one of the premises (scil., ‘all rational things are risible’) is left unspoken.

Furthermore, when we argue with others we’re not dealing with pure intellects but we must contend with the interference of emotion. Emotion either can have no role in reasoning (and this is ideal because emotion per se is foreign to the pursuit of truth) or it can hinder reasoning (as when passion compels me to reject something which is true merely because I dislike the person who said it) or it can be used to the benefit of reasoning (as when a person who would otherwise not hear what I have to say can be made amenable because of a pleasant and amiable approach). The study of how to use the emotions in argument is called poetics—as the Doctor says “the poet’s vocation is to guide us to what is virtuous by presenting it as attractive.” Through poetics we learn how to make reasoning palatable to another because of a pleasing representation, or the desirable way in which that reasoning process is presented. But it must be understood that emotions do not have a primary and per se connection to argument and truth. Hence, the value of poetics is only supplementary and should never be used where it isn’t necessary to prepare or aid the mind of the hearer. To employ it where it isn’t necessary is to introduce a useless danger: the danger that emotions might unduly influence the judgment of the mind—as Aristotle says, “one might as well warp a carpenter’s rule before using it.”

2) Is the explicit use of syllogisms the only way to write?

Everything I said about argumentation in general can be applied to answering this question because writing is a kind of argumentation, as are spoken argumentation and gesticulatory argumentation.

3) Whether everyone who makes an argument employs syllogisms implicitly or explicitly.

Taking argument in the strict meaning that we’ve given it here, then, yes, this is true. Everyone who argues—in the strict sense—signifies the reasoning process to another and, by definition, the signification of a reasoning process is a syllogism. But in a wider sense, if we mean by ‘argument’ any attempt to cause someone to accept a point (i.e., not necessarily through reasoning), then we must admit that not everyone uses a syllogism. A syllogism signifies a reasoning process whereby a conclusion is caused by its premises. Now, many attempt to establish a point not because it follows as a conclusion to previous knowledge, but because the mind is inclined to believe it, as in the case of rhetorical argument, or because the point is pleasing, as in the case of poetical argument. Therefore, not everyone who makes an argument—in a wide meaning—employs a syllogism.

Furthermore, sometimes something is signified that resembles a rational process but, in fact, the conclusion is not really caused by the premises because of some defect in the form of the argument—this is a fallacy or, if done with an intent to deceive, a sophism. But fallacies and sophisms are often used to compel another to accept a point. Therefore, not everyone who makes an argument—again, in a wide sense—employs syllogisms.

Nevertheless, we should say that syllogisms are the clearest representation of reasoning and by the use of syllogistic form we can the more easily identify errors in rational discourse. Especially at the beginning of logical studies it’s expedient to make frequent use of strictly logical form so that we can see the relations between our concepts and judgments.


What is Logic and why Should We Study Logic?

By Jean Oesterle

We might begin our answer to this question by observing that everyone naturally desires to know. This self-evident statement simply that a human being is so constituted that he cannot help wanting to know. A human being is a knowing being.

But what kind of knowing? We know in various ways. For example, I know that a dinner is cooking by smelling it. I know that a man is in a chair by looking at him. I know what New York looks like by remembering my visit there a year ago. In a more complex way than in any of the preceding examples, I know that sooner or later I shall die; even more, I know that every man dies and why every man must die.

What kind of knowing do we mean, then, when we say that everyone naturally desires to know? In the sense that every human being is so constituted that he cannot help wanting to know, every kind of knowing is included. But if we take the statement to mean the kind of knowing with which a human being is distinctively concerned, then the statement applies properly to the last kind of knowing. The last kind of knowing is reasoned knowledge.

What do we mean by reasoned knowing? It is that kind of knowing by which we find out why this or that is so. Thus, if someone asks me why every man must die—why every man is mortal—I have to give him some reason for accepting the statement as true. In brief, I have to prove it. This kind of knowing is distinctively human knowing for we do not go about proving to horses or cows or even apes that they too must dies, although it is just as true that they die as it is that human beings die.

All human beings, then, in varying degrees want to know why things are so. An evident sign of this is that even as children we frequently ask for the why of things. We are insatiably curious. This universal wonder of human beings is never entirely smothered, although we often disregard its promptings. As the ancient Greeks declared, wonder is the starting point of knowledge, Wonder is the starting point in the sense that we wonder what can be the explanation of cause of the things that we are continually observing. IT is only when we do not know the cause of a thing that our wonder ceases about that thing, for only by knowing the cause is our wonder fully satisfied.

Now logic is nothing else than the art that guides us in coming to know something previously unknown to us. Logic, then, is an instrument for helping us to find out why things are as they are. An axe is an instrument for cutting down a tree. A sharp axe is an efficient instrument for cutting down a tree. The power of thinking is an instrument for knowing the why and wherefore of things, but thinking sharpened by skill in logic is an efficient instrument for scientific knowing. We thus have at least a preliminary answer to what logic is and why we should study it. If every human being wants to know, in some degree, and if logic is an indispensable means of obtaining knowledge more easily, more surely, and more efficiently, then the study of logic is of use to every human being.

Let us now investigate in greater detail what logic is about and how we reason in a logical way. Suppose that you were walking down a street on a wintry day after a heavy snowfall. The sun is out and shining brightly. You notice the shining of the sun in particular because your eyes are bothered by the reflection of the sun on the snow. The thought might occur to you how much the snow reflects the light of the sun. This thought, in turn, might call your attention to the whiteness of the snow. You would recognize at once that the whiteness of the snow was the reason for the bright reflection of the snow in your eyes.

In this very ordinary example, you have informally gone through a reasoning process. You started with the statement Snow reflects light. You proceeded almost immediately to give the reason why snow reflects light, namely, snow is white. The first statement follows from the second statement, and the two statements can be put down in the following order:

Snow is white.

Therefore, snow reflects light.

The word “therefore” indicates that the second statement follows as a conclusion from the first. Now if you analyze these two statements, you will notice that there is a third statement implicitly contained in them, a statement containing the words “white” and “light.” This third statement would reason: white reflects light. You would then have three statements, appearing in the following order:

White reflects light.

Snow is white.

Therefore, snow reflects light.

This full argument is called a syllogism. It is a movement of our power of reasoning that grasps the truth of a conclusion by seeing the truth and connection of the two propositions leading to the conclusion. Logic guides us in knowing how to construct an argument like this, a kind of knowing, as we shall see, that is demonstrative knowledge. But to know what a syllogism is, and how to construct a syllogism, we have to know the parts of a syllogism, just as we have to know the different parts of a house in order to build a house.

The most immediate parts of a syllogism are the propositions of which it is composed. Logic will help us to understand what propositions are, and what their relation is to each other, so that from them we can make good arguments, or syllogism, and thus demonstrate what we know.

There are, however, other parts of a syllogism besides propositions. Words, which signify concepts, also make up a syllogism; for instance, “snow”, “light,” and “white” were parts of the syllogism given above. Words, in fact, are parts of propositions as well as parts of syllogisms. The words “snow” and “white” were parts of the proposition Snow is white. “Snow” and “white” are also parts of the syllogism given above, but they are parts of a syllogism differently from the way in which they are parts of a proposition, as we shall see later.

The syllogism given above was chosen deliberately to bring out the need of knowing the parts of a proposition before knowing the whole proposition; it also brings out the need of knowing the parts of a syllogism before knowing the whole syllogism. Clearly we have to know what various words mean before we put them into propositions and we have to know whether propositions are true before we can construct a sound argument out of them. Thus, in the given syllogism we have to know what “snow” means and what “white” means—we have to be able to define the words—before we can determine whether the proposition is true or not. And then, before we can give a full syllogism, we must further know the structure of a proposition, and how to determine when a proposition is true. Finally, in giving the full syllogism, we have to know how to relate propositions to each other and infer a conclusion from them.

We can now see the extent of an elementary course in Logic. There are three main topics to be considered: 1) definition 2) proposition and 3) syllogism. Each of these belongs to a different act of the human intellect.

Definition is known by the act of simple apprehension. The act of simple apprehension is the way in which we grasp a simple object, such as man or dog or horse. This is the first act of the human intellect, and we express these simple notions by definitions. We must know such simple objects first before we can combine simple objects into the complex structure of a proposition. In short, we must know the definitions of dog and animal before we can combine them into the proposition every dog is an animal.

The proposition (also called an enunciation) is known by the intellectual act of composition and division of terms, in which truth or falsity appears. If we combine or compose two terms, as in every dog is an animal, we have an affirmative proposition. If we divide or deny two terms of each other, as in no horses are dogs, we have a negative proposition.

The syllogism is known by the act of reasoning, in which we proceed from one thing to another. More specifically, by knowing two propositions as true and as related in a certain way to each other, we reason to a third proposition concluding from them. Thus, by knowing every mammal is an animal and Every cow is a mammal, we arrive at the reasoning knowledge Every cow is an animal. Let us recall here that we originally spoke of logic as the art that guides us in coming to know the unknown. There are , actually, only two kinds of unknown objects: a simple object, such as man, and a complex object, such as man is artistic. Let us relate the two kinds of unknown objects to the three acts of the intellect listed above.

As we have seen, a simple object is made known by the first act of the intellect, which we called simple apprehension. The principal means of knowing a simple object is by defining it. A sign that we know the simple object man is the definition that we give of man. Since the purpose of the first act of the intellect is to arrive at definitions, this act is guided by the part of logic that we call the art of defining.

A complex object is made known by means of argumentation. But argumentation requires two additional acts of the intellect: the act of composition or division and the act of reasoning. Hence, the second act of the intellect combines the simple objects that have been made known by the first act of the intellect in definition; it divides them by denying one of the other. If such a combination or division is not self-evident, then it must be manifested by argumentation, and because of this, a third act of the intellect is necessary. The third act is the reasoning process by which we proceed from propositions made known by the second act of the intellect to a conclusion following from these propositions.

From this discussion we can now give a definition of logic: Logic is the art that directs the three acts of the intellect.

Mercier’s Daily Definitions

Objectivity (real): The relation of conformity between an object of knowledge and some reality independent of mental representation.

Obligation (moral): The practical imperative necessity of freely doing what is morally good and of freely avoiding what is morally evil.

A circumstance or combination of circumstances favourable to the action of a free cause. ‘Quaedam causa per accidens est quae aliquid operatur, non tamen pertingit ejus operatio usque ad effectum conjunctum . . . et talis causa dicitur proprie occasio’ (In I Sent., dist. 46, q. 1, a. 2, ad 3). ‘Occasio nominat causam per sensufficientem . . . sed inducentem’ (In IV Sent., I, q. 1, a. 7).

Mercier’s Daily Definitions

Object (of a faculty): That to which the exercise of a faculty applies. ‘Objectum non est materia ex qua, sed materia circa quam et habet quodammodo rationem formae in quantum dat speciem’ (Sum. Theol., I-II, q. 18, a. 2, ad 2).

The object of knowledge is that wherein the act of knowledge rests and by which it is completed. ‘Objectum operationis terminat et perficit ipsam est finis ejus’ (In I Sent., dist. I, q. 2, a. 1, ad 2).

The material object is something of which the special point view for consideration is not determined; whilst the formal object is that special point of view from which a thing is dealt with by a faculty.

The proper object of a faculty is what falls immediately within the range and for the attainment of which it is made; the improper object is something it cannot attain to except through the medium of the proper object. ‘Proprium (id est formale) objectum alicujus potentiae est illud sub cujus ratione omnia referuntur ad potentiam’ (Sum. Theol., I, q. 1, a. 7).