LOGIC

A.F.Uduicwomen, Ph.D,"How To Think" AAu. Uitalis Book Company 50 Samek Road, Ariaria Aba (2003) pg 13
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Alfred Tarski, Introduction to Logic and to the Methodology of the Deductive Sciences, trans. from Polish, 5th ed. (2009); P.76.
Richard Montague, and Gary Mar, Logic: Techniques of Formal Reasoning, 2nd ed. (1980, reissued 1992); p.87.
Richard H. Popkin,ph.D, and Avrum Stroll, ph.D. "Philosophy made Simple" New York (1921) pg 237.

Turner, W. (1910). Logic In The Catholic Encyclopedia. New York: Robert Appleton Company. Retrieved April 26, 2010 from New Advent: http://www.newadvent.org/cathen/09324a.htm

Turner, William. "Logic." The Catholic Encyclopedia. Vol. 9. New York: Robert Appleton Company, 1910. 26 Apr. 2010
O.A. Oyeshile, Ph.D and Lio Ugwuanyi, ph.D, "Elements of Philosophy and Logic", pg 127


Damian Tersoo Anyam, Ph.D, "Makurdi Philosophy, Logic and Human Existence" philosophy Unit Department of Religion and Philosophy, Benue State University, (2013) pg 74

APA citation. Turner, W. (1910). Logic. In The Catholic Encyclopedia. New York: Robert Appleton Company. Retrieved April 26, 2010 from New Advent: http://www.newadvent.org/cathen/09324a.htm

INTRODUCTION
The study of correct reasoning, especially as it involves the drawing of inferences is one of the most important branches of philosophy. One who acquires knowledge must take or have a right principle to make use of the knowledge acquired. This work discusses the basic definition and meaning, beginning with its etymology, scope and basic concept of logic, view of logic by some philosophers, divisions of logic, history of logic and most importantly the relevance of logic to seminarians.
DEFINITION AND MEANITION OF LOGIC
Etymology
The Greek word logos, meaning "reason", is the origin of the term logic--logike (techen, pragmateia, or episteme, understood), as the name of a science or art, first occurs in the writings of the Stoics. Aristotle, the founder of the science, designates it as "analytic" and the Epicureans use the term canonic. From the time of Cicero, however, the word logic is used almost without exception to designate this science. The names dialectic and analytic are also used.
The definition
It is a curious fact that, although logic is the science which treats of definition, logicians are not agreed as to how logic itself should be defined. There are, in all, about two hundred different definitions of logic. It would, of course, be impossible to enumerate even the principal definitions here. It will be sufficient to mention and discuss a few typical ones. Logic is the science and art which so directs the mind in the process of reasoning and subsidiary processes as to enable it to attain clearness, consistency, and validity in those processes. The aim of logic is to secure clearness in the definition and arrangement of our ideas and other mental images, consistency in our judgments, and validity in our processes of inference.S
Scope and basic concept
An inference is a rule-governed step from one or more propositions, called premises, to a new proposition, usually called the conclusion. A rule of inference is said to be truth-preserving if the conclusion derived from the application of the rule is true whenever the premises are true. Inferences based on truth-preserving rules are called deductive, and the study of such inferences is known as deductive logic. An inference rule is said to be valid, or deductively valid, if it is necessarily truth-preserving. That is, in any conceivable case in which the premises are true, the conclusion yielded by the inference rule will also be true. Inferences based on valid inference rules are also said to be valid.
VIEW OF LOGIC BY SOME PHILOSOPHERS
Port Royal
The Port Royal logic ("L'Art de penser", published 1662) defines logic as "the art of using reason well in the acquisition of the knowledge of things, both for one's own instruction and that of others." More briefly "Logic is the art of reasoning." The latter is Arnauld's definition. Definitions of this type are considered too narrow, both because they define logic in terms of art, not leaving room for its claim to be considered a science, and because, by the use of the term reasoning, they restrict the scope of logic to one class of mental processes.
Hegel
Hegel (see HEGELIANISM) goes to the other extreme when he defines logic as "the science of the pure idea." By idea he understands all reality, so that for him logic includes the science of subjective reality (logic of mental concepts) and the science of objective reality (logic of being, metaphysics). In like manner the definitions which fail to distinguish between logic and psychology, defining logic as "the science of mental processes", or "the science of the operations of the mind", are too wide. Definitions which characterize logic as "the science of sciences", "the art of arts", are also too wide: they set up too large a claim for logic.
LOGIC AS A SCIENCE DISCIPLINE
The question whether logic is a science or an art is now generally decided by asserting that it is both. It is a science, in so far as it not merely formulates rules for right thinking, but deduces those rules from general principles which are based on the nature of mind and of truth. It is an art, in so far as it is directly and immediately related to performance, namely, to the acts of the mind. As the fine arts direct the painter or the sculptor in the actions by which he aims at producing a beautiful picture or a beautiful statue, so logic directs the thinker in the actions by which he aims at attaining truth, or expounding truth which he has attained.
Division of logic
The traditional mode of dividing logic, into "formal" and "material", is maintained in many modern treatises on the subject. In Formal logic the processes of thought are studied independently of, or without consideration of, their content. In Material logic the chief question is the truth of the content of mental processes. An example from arithmetic will serve to illustrate the function of formal logic. When we add two and two, and pronounce the result to be four, we are dealing with a process of addition in its formal aspect, without paying attention to the content. The process is valid whatever the content may be, whether the "two and two "refer to books, horses, trees, or circles. This is precisely how we study judgments and arguments in logic. From the judgment "All A is B" we infer "Therefore some B is A"; and the process is valid whether the original proposition be "All circles are round" or "All lions are carnivorous". In material logic, on the contrary, we inquire into the content of the judgments or premises and endeavour to determine whether they are true or false. Material logic was styled by the old writers "major logic", "critical logic", or simply" criticism". In recent times the word epistemology (science of knowledge), meaning an inquiry into the value of knowledge, has come into general use, and designates that portion of philosophy which inquires into the objective value of our concepts, the import and value of judgments and reasoning, the criteria of truth, the nature of evidence, certitude, etc. Whenever this new term is adopted there is a tendency to restrict the term logic to mean merely formal logic. Formal logic studies concepts, and other mental images, for the purpose of securing clearness and order among those contents of the mind. It studies judgments for the purpose of showing when and how they are consistent or inconsistent, that is, when one may be inferred from another (conversion), and when they are opposed (opposition) . It studies the two kinds of reasoning, deductive and inductive, so as to direct the mind to use these processes validly. Finally, it studies sophisms (or fallacies) and method for the purpose of showing what errors are to be avoided, and what arrangement is to be followed in a complex series of reasoning processes. But, while it is true in general that in all these tasks formal logic preserves its purely formal character, and does not inquire into the content of thought, nevertheless, in dealing with inductive reasoning and in laying down the rules for definition and division, formal logic does take account of the matter of thought. For this reason, it seems desirable to abandon the old distinction between formal and material, to designate as logic what was formerly called formal logic, and to reserve the term epistemology for that portion of philosophy which, while inquiring into the value of human knowledge in general, covers the ground which was the domain of material logic.
There remain certain kinds of logic which are not included under the heads formal and material. Transcendental logic (Kant) is the inquiry into human knowledge for the purpose of determining what elements or factors in human thought are a priori, that is, independent of experience. Symbolic logic (Lambert, Boole) is an application of mathematical methods to the processes of thought. It uses certain conventional symbols to represent terms, propositions, and the relations among them, and then, without any further reference to the laws of thought, applies the rules and methods of the mathematical calculus (Venn, "Symbolic Logic", London, 1881). 5.0. HISTORY OF LOGIC
The history of logic possesses a more than ordinary interest, because, on the one hand, every change in the point of view of the metaphysician and the psychologist tended to produce a corresponding change in logical theory and practice, while, on the other hand, changes in logical method and procedure tended to affect the conclusions as well as the method of the philosopher. Notwithstanding these tendencies towards variation, the science of logic has undergone very few radical changes from the beginning of its history.
The Nyaya
A ystem of philosophy which was studied in India in the fifth century B.C., though it is perhaps, of much older date, takes its name from the word nyaya, meaning logical argument, or syllogism. This philosophy, like all the Indian systems, busied itself with the Problem of the deliverance of the soul from bondage, and its solution was that the soul is to be freed from the trammels of matter by means of systematic reasoning.The nyaya, or Indian syllogism, as it is sometimes called, consists of five propositions. If, for instance, one wishes to prove that the hill is on fire, one begins with the assertion: "The hill is on fire." Next, the reason is given: "For it smokes." Then comes an instance, "Like the kitchen fire"; which is followed by the application, "So also the hill smokes." Finally comes the conclusion, "Therefore it is on fire." Between this and the clear-cut Aristotelean syllogism, with its major and minor premises and conclusion, there is all the difference that exists between the Oriental and the Greek mode of thinking. It is hardly necessary to say that there is no historical evidence that Aristotle was in any way influenced in his logic by Gotama, the reputed author of the nyaya.
Pre-Aristotelian logic in Greece
The first philosophers of Greece devoted attention exclusively to the problem of the origin of the universe ( Ionian School of Philosophy). The Eleatics, especially Zeno of Elea, the Sophists, and the Megarians developed the art of argumentation to a high degree of perfection. Zeno was especially remarkable in this respect, and is sometimes styled the Founder of Dialectic. None of these, however, formulated laws or rules of reasoning. The same is true of Socrates and Plato, although the former laid great stress on definition and induction, and the latter exalted dialectic, or discussion, into an important instrument of philosophical knowledge.
Aristotle, the founder of logic
In the six treatises which he devoted to the subject, Aristotle examined and analysed the thinking processes for the purpose of formulating the laws of thought. These treatises are
"The Categories",
"Interpretation",
"Prior Analytics",
"Posterior Analytics",
"Topics", and
"Sophisms". These were afterwards given the title of "Organon", or "Instrument of Knowledge"; this designation, however, did not come into common use until the fifteenth century.
The first four treatises contain, with occasional excursions into the domain of grammar and metaphysics, the science of formal logic essentially the same as it is taught at the present day. The "Topics" and the "Sophisms" contain the applications of logic to argumentation and the refutation of fallacies. In conformity with the fundamental principle of his theory of knowledge, namely, that all our knowledge comes from experience, Aristotle recognizes the importance of inductive reasoning, that is to say, reasoning from particular instances to general principles. If he and his followers did not develop more fully this portion of logic, it was not because they did not recognize its importance in principle. His claim to the title of Founder of Logic has never been seriously disputed the most that his opponents in the modern era could do was to set up rival systems in which induction was to supplant syllogistic reasoning. One of the devices of the opponents of scholasticism is to identify the Schoolmen and Aristotle with the advocacy of an exclusively deductive logic.
Modern logic
The fifteenth century witnessed the first serious attempts to revolt against the Aristotelean logic of the Schools. Humanists like Ludovicus Vico and Laurentius Valla made the methods of the Scholastic logicians the object of their merciless attack on medievalism. Of more importance in the history of logic is the attempt of Ramus (Pierre de La Ramee, 1515-72) to supplant the traditional logic by a new method which he expounded in his works "Aristotelicae Animadversiones" and "Scholae Dialecticae". Ramus was imitated in Ireland by George Downame (or Downham), Bishop of Derry, in the seventeenth century, and in the same century he had a most distinguished follower in England in the person of John Milton, who, in 1672, published "Artis Logicae Plenior Institutio ad Petri Rami Methodum Concinnata". Ramus's innovations, however, were far from receiving universal approval, even among Protestants. Melanchthon's "Erotemata Dialectica", which was substantially Aristotelean, was extensively used in the Protestant schools, and exerted a wider influence than Ramus's "Animadversiones". Francis Bacon (1561-1626) inaugurated a still more formidable onslaught. Profiting by the hints thrown out by his countryman and namesake, Roger Bacon (1214-1294), he attacked the Aristotelean method, contending that it was utterly barren of results in science, that it was, in fact, essentially unscientific, and needed not so much to be reformed as to be entirely supplanted by a new method. This he attempted to do in his "Novum Organum", which was to introduce a new logic, an inductive logic, to take the place of the deductive logic of Aristotle and the Schoolmen. Neither did Descartes (1596-1649), who was as desirous to make logic serve the purposes of the mathematician as Bacon was to make it serve the cause of scientific discovery. The Port Royal Logic ("L'Art de penser" 1662), written by Descartes's disciples, is essentially Aristotelean. So, though in a less degree are the logical treatises of Hobbes (1588-1679) and Gassendi (1592-1655), both of whom underwent the influence of Bacon's ideas. In the seventeenth and eighteenth centuries, Father Buffier, Le Clerc (Clericus), Wolff, and Lambert strove to modify the Aristotelean logic in the direction of empiricism, sensism, or Leibnizian innatism. In the treatises which they wrote on logic there is nothing that one might consider of primary importance.
Kant and the other German Transcendentalists of the nineteenth century took a more equitable view of Aristotle's services to the science of logic. As a rule, they recognized the value of what he had accomplished and, instead of trying to undo his work, they attempted to supplement it. It is a question, however, whether they did not do as much harm to logic in one way as Bacon and Descartes did in another. By withdrawing from the domain of logic what is empirical, and confining the science to an examination of "the necessary laws of thought", the Transcendentalists gave occasion to Mill and other Associationists to accuse logic of being unreal, and out of touch with the needs of an age which was, above all things, an age of empirical science. Most of the recent German literature on logic is characterized by the amount of attention which it pays either to historical inquiries, or to inquiries into the value of knowledge, or to investigation of the philosophical foundations of the laws of logic.
7.0.RELEVANCE OF LOGIC IN THE FORMATION OF SEMINARIANS
Nowadays, people listen to Seminarians speak not so much to gain the message of salvation promised by our Lord Jesus Christ from them but to find out the mistakes they will make, the wrong use of terms, how out spoken the seminarian is, the heresies and fallacies spoken by the seminarian. A seminarian can be called to give a speech at any time therefore the Church been aware of the challenges she face today has thought as wise the need to study logic in the seminary because it will enable the seminarian training to become a priest to reason, to speak with clarity, without feebleness, ambiguity, tautology and inability to express one's self and also to archive the following;
Logic helps us to develop system of methods and principles that we may use as criteria for evaluating the argument of others and guides us in constructing arguments of our own which will help us as seminarians to grow spiritually and physically closer to God.
As a seminarian training to become a priest, Logic helps to set principles which will guide in the moral, human, intellectual and spiritual formation. The principles can serve as aid in forming the mind of the individual towards achieving the goal of becoming a priest and when the seminarian becomes a priest, it will serve as an aid towards achieving the pastoral goal of every priest which is winning souls for God.
Logic guards us against many pitfalls of errors on our part and against the uncritical acceptance of statements made by others.
It is no doubt that logicians are or have a very good method of communication skills as a result of this the study of logic will help a seminarian to be a n effective communicator since all of his work is concern with communication.
The study of logic in the Seminary will help a seminarian to sharpens, guides, or shapes our reasoning process.
It helps in the attainment of truth in discourse i.e following the process. It helps the seminarians to avoid jumping into unjustifiable conclusion.
It increases confidence that we are making sense when we criticize the arguments of others and when we advance our own arguments and therefore it builds the moral in us.
Logic helps seminarians to detect fallacies in reasoning and correct inaccuracies in speaking and write ups by other people.
Logic helps seminarians to speak and write with clarity, precision and tenacity. Thus it helps seminarian to overcome vagueness, feebleness, ambiguity, tautology and woolliness of expression in the mater we have set forth to discuss or talk about.
Logic helps to weigh the merits and demerits of an action.Discernment between what is good and what is bad is very important in this line of vocation. It is important for someone to know the consequences of an action before venturing into it. Logic helps to give a clear understanding towards the consequences of an action. It will aid the individual towards doing what is right or wrong if the individual reasons the consequences.
Logic helps to construct arguments. Oppositions to the catholic faith is bound to arise and arguments from all areas might come. Though the religious or the clergy might not have all the knowledge in that area, with the aid of logical reasoning, the religious or clergy is able to argue and stand out in his argument and not only win arguments but convert souls to God.
CONCLUSION
In every system of logic there is an underlying philosophical theory, though this is not always formulated in explicit terms. It is impossible to explain and demonstrate the laws of thought without falling back on some theory of the nature of mind. For this reason Catholic philosophers and educators, as well as those who by their position in the Church are responsible for the purity of doctrine in Catholic institutions, have recognized that there is in logic the Catholic and the non-Catholic point of view. Our objection to a good deal of recent logical literature is not based on an unfavourable estimate of its scientific quality: what we object to is the sensism, subjectivism, agnosticism or other philosophical doctrine, which underlies the logical theories of the author. Works on logic written by Catholics generally adhere very closely to the traditional Aristotelean logic of the schools. Yet that is not the reason why they are approved. They are approved because they are free from false philosophical assumptions. In many non-Catholic works on logic the underlying philosophy is not only erroneous, but subversive of the whole body of natural spiritual truth which the Catholic Church guards as carefully as she does the deposit of faith.
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