Logic and CT Lecture Notes 1 (Chapters 15 wo 4) PDF

CHAPTER ONE : Defining PHILOSOPHY Compiled by : Mohammed z.  OUTLINE EARLIEST PHILOSOPHERS MEANING OF PHILOSOPHY NATURE OF PHILOSOPHY BRANCHES OF PHILOSOPHY RELEVANCE OF PHILOSOPHY 2  THE EARLIEST PHILOSOPHERS To define...

CHAPTER ONE : Defining PHILOSOPHY Compiled by : Mohammed z.  OUTLINE EARLIEST PHILOSOPHERS MEANING OF PHILOSOPHY NATURE OF PHILOSOPHY BRANCHES OF PHILOSOPHY RELEVANCE OF PHILOSOPHY 2  THE EARLIEST PHILOSOPHERS To define philosophy better, we need to look in to philosophers themselves. The best way to do so is to start from the pre-Socratic (the earliest philosophers). Why we are interested in the earliest Greek philosophers? Is it because no philosophers anywhere else in the world ? No ! We are interested in the earliest western philosophers because they were the first systematic philosophers in the history of mankind to have well documented and systematically arranged body of thoughts transmitted through generations. 3  The earliest Western philosophers were Greeks: men who spoke dialects of the Greek language, who were familiar with the Greek poems of Homer and Hesiod, and who had been brought up to worship Greek Gods like Zeus, Apollo, and Aphrodite. They lived not on the mainland of Greece, on the southern coasts of Italy or on the western coast of what is now Turkey. These early philosophers were also early scientists, and several of them were also religious leaders. 4  In the beginning the distinction between science, religion, and philosophy was not as clear as it became in later centuries. In the sixth century, in Asia Minor and Greek Italy, there was an intellectual cauldron in which elements of all these future disciplines fermented together. Later, religious devotees, philosophical disciples, and scientific inheritors could all look back to these thinkers as their forefathers 5  Pythagoras, who was honored in antiquity as the first to bring philosophy to the Greek world. He has a claim to be the founder of geometry as a systematic study. His name became familiar to many generations of schoolchildren because he was credited with the first proof that the square on the long side of a right-angled triangle is equal in area to the sum of the squares on the other two sides. he also founded a religious community with a set of ascetic and ceremonial rules, the best-known of which was a prohibition on the eating of beans. He taught the doctrine of the transmigration of souls: human beings had souls which were separable from their bodies, and at death a person's soul might migrate into another kind of animal. 6  he taught his disciples to abstain from meat; once, it is said, he stopped a man whipping a puppy, claiming to have recognized in its whimper the voice of a dear dead friend. He believed that the soul, having migrated into different kinds of animal in succession, was eventually reincarnated as a human being. He himself claimed to remember having been, some centuries earlier, a hero at the siege of Troy. 7  The Milesians (Ionians) Pythagoras’ life is lost in legend. Rather more is known about a group of philosophers, roughly contemporary with him, who lived in the city of Miletus in Ionia. The first of these was Thales, who was old enough to have foretold an eclipse in 585. Like Pythagoras, he was a geometer, though he is credited with rather simpler theorems, such as the one that a circle is bisected by its diameter. Like Pythagoras, he mingled geometry with religion: when he discovered how to inscribe a right-angled triangle inside a circle, he sacrificed an ox to the gods. But his geometry had a practical side: he was able to measure the height of the pyramids by measuring their shadows. He was the first Greek to fix the length of the year as 365 days, and he made estimates of the sizes of the sun and moon. 8  The Milesians (Ionians) Pythagoras’ life is lost in legend. Rather more is known about a group of philosophers, roughly contemporary with him, who lived in the city of Miletus in Ionia. The Milesians were physiologists. As they attempted to provide a rational account or '"logos" of nature, the Greek word for nature being "physics”. Hence, the word physiologist, or one who provides a logos of physis. Note that today the word "physiologist" has a different meaning. In attempting to give a rational account of nature, Thales, Anaximander, and Anaximenes were all interested in the fundamental question, what is the world made of? Looking out into the world, they noted that reality displays two fundamental characteristics; firstly, everything in the world is constantly changing or constantly in flux. This is why philosophers often call the world we perceive a "world of becoming" as everything is always becoming something else. 9 Secondly, they observed that there is an infinite plurality of different things in the world. In other words, any single thing that exists is different than anything else that exists, has existed, or will ever exist. The world displays infinite variation. When the Milesians asked what is the world made of they concluded that underlying the plurality of things in this world and underneath all the transformations these things undergo, there exists a single and permanent substance, in other words; they proposed that everything in the world is made of the same stuff and that this stuff although undergoing modifications in this world always retains its unity and fundamental identity. 10  This material substance underlying the world the Ancient Greeks called the "Arche". the Arche is the underlying source and origin of all things, but what does he mean when he says that the Arche was thought of as the ruler or as exerting authority? The Arche is the underlying substance and source of all things. it was thought by the Milesians to be a physical or corporeal material as the concept of immaterial spirit, or pure mind had not yet been arrived at by the Greeks. However, at the same time, this underlying substance was thought to be alive and endowed with spirit. Considered divine and imbued with intelligence. The Arche, being alive, was, therefore, the author of its own movement or self-caused. Hence was the ruler of all things. In addition, exerted its authority by guiding the birth, transformations, and death of all things. 11  Thales was perhaps the first philosopher to ask questions about the structure and nature of the cosmos as a whole. For Thales the Arche was water. He maintained that the earth rests on water, like a log floating in a stream. (Aristotle asked, later: what does the water rest on?) According to Thales, earth and its inhabitants did not just rest on water: they were all made out of water. Even in antiquity, people could only conjecture the grounds for this belief: because all animals and plants need water, or because the seeds of everything are moist. 12  Because of his theory about the cosmos, Thales was called by later writers a physicist or philosopher of nature (‘physis’ is the Greek word for ‘nature’). Though he was a physicist, Thales was not a materialist: he did not believe that nothing existed except physical matter. One of the two sayings which have come down from him verbatim is ‘everything is full of gods’. He did not believe in Pythagoras’ doctrine of transmigration, but he did maintain the immortality of the soul. 13  Thales was no mere theorist. He was a political and military adviser to King Croesus of Lydia, and helped him to ford a river by diverting a stream. Foreseeing an unusually good olive crop, he took a lease on all the oil-mills, and made a fortune. 14  A more significant thinker was a younger contemporary and pupil of Thales called Anaximander, a savant who made the first map of the world and of the stars He taught that the earth was cylindrical in shape, like a section of a pillar. Around the world were gigantic tires, full of fire; each tire had a hole through which the fire could be seen, and the holes were the sun and moon and stars. The largest tire was twenty-eight times as great as the earth, and the fire seen through its orifice was the sun. Blockages in the holes explained eclipses and the phases of the moon. The fire within these tires was once a great ball of flame surrounding the infant earth, which had gradually burst into fragments which enrolled themselves in bark-like casings. Eventually the heavenly bodies would return to the original fire. 15  Though fire played an important part in Anaximander’s cosmogony, it would be wrong to think that he regarded it as the ultimate constituent of the world, like Thales’ water. The basic element of everything, he maintained, could be neither water nor fire, nor anything similar, or else it would gradually take over the universe. It had to be something with no definite nature, which he called the ‘infinite’ or ‘unlimited’. ‘The infinite is the first principle of things that exist: it is eternal and ageless, and it contains all the worlds. 16  Anaximander was an early proponent of evolution. The human beings we know cannot always have existed, he argued. Other animals are able to look after themselves, soon after birth, while humans require a long period of nursing; if humans had originally been as they are now they could not have survived. He maintained that in an earlier age there were fish-like animals within which human embryos grew to puberty before bursting forth into the world. Because of this thesis, though he was not otherwise a vegetarian, he preached against the eating of fish. 17  The infinite of Anaximander was a concept too esoteric for some of his successors. His younger contemporary at Miletus, Anaximenes, while agreeing that the ultimate element could not be fire or water, claimed that it was air, from which everything else had come into being. In its stable state, air is invisible, but when it is moved and condensed it becomes first wind and then cloud and then water, and finally water condensed becomes mud and stone. Rarefied air, presumably, became fire, completing the gamut of the elements. In support of his theory, Anaximenes appealed to experience: ‘Men release both hot and cold from their mouths; for the breath is cooled when it is compressed and condensed by the lips, but when the mouth is relaxed and it is exhaled it becomes hot by reason of its rareness.’ Thus rarefaction and condensation can generate everything out of the underlying air. This is naive, but it is naive science: it is not mythology. 18  XENOPHANES Thales, Anaximander, and Anaximenes were a trio of hardy and ingenious speculators. Their interests mark them out as the forebears of modern scientists rather more than of modern philosophers. The matter is different when we come to Xenophanes who lived in the fifth century BC. His themes and methods are recognizably the same as those of philosophers through succeeding ages. In particular he was the first philosopher of religion, and some of the arguments he propounded are still taken seriously by his successors. 19  Xenophanes detested the religion found in the poems of Homer and Hesiod, whose stories blasphemously attributed to the gods theft, trickery, adultery, and all kinds of behaviour that, among humans, would be shameful and blameworthy. A poet himself, he savaged Homeric theology in satirical verses. It was not that he claimed himself to possess a clear insight into the nature of the divine; on the contrary, he wrote, ‘the clear truth about the gods no man has ever seen nor any man will ever know’. But he did claim to know where these legends of the gods came from: human beings have a tendency to picture everybody and everything as like themselves. Ethiopians, he said, make their gods dark and snub-nosed, while Thracians make them red-haired and blue-eyed. The belief that gods have any kind of human form at all is childish anthropomorphism. ‘If cows and horses or lions had hands and could draw, then horses would draw the forms of gods like horses, cows like cows, making their bodies similar in shape to their own.’ 20  Though no one would ever have a clear vision of God, Xenophanes thought that as science progressed, humans could learn more than had been originally revealed. ‘There is one god,’ he wrote, ‘greatest among gods and men, similar to humans neither in shape nor in thought.’ God was neither limited nor infinite, but altogether non- spatial: that which is divine is a living thing which sees as a whole, thinks as a whole, and hears as a whole. In a society which worshipped many gods, he was a resolute monotheist. There was only one God, he argued, because God is the most powerful of all things, and if there were more than one, then they would all have to share equal power. God cannot have an origin; because what comes into existence does so either from what is like or what is unlike, and both alternatives lead to absurdity in the case of God. God is neither infinite nor finite, neither changeable nor changeless. But though God is in a manner unthinkable, he is not unthinking. On the contrary, ‘Remote and effortless, with his mind alone he governs all there is.’ 21  While traditional religions took their stance on the basis of a divine oracle, Xenophanes offered to prove his point by rational argument. Xenophanes’ philosophy of nature is less powerful than his philosophy of religion. His views are variations on themes proposed by his Milesian predecessors. He took as his ultimate element not water, or air, but earth. The earth, he thought, reached down beneath us to infinity. The sun, he maintained, came into existence each day from a congregation of tiny sparks. But it was not the only sun; indeed there were infinitely many. Xenophanes’ most original contribution to science was to draw attention to the existence of fossils: he pointed out that in Malta there were to be found impressed in rocks the shapes of all sea-creatures. From this he drew the conclusion that the world passed through a cycle of alternating terrestrial and marine phases. 22  HERACLITUS The last, and the most famous, of these early Ionian philosophers was Heraclitus. Heraclitus denounced the worship of the temple: praying to statues was like whispering gossip to an empty house, and offering sacrifices to purify oneself from sin was like trying to wash off mud with mud. He visited the temple from time to time, but only to play dice with the children there – much better company than statesmen, he said, refusing to take any part in the city’s politics. 23  Heraclitus spoke of a great Word or Logos which holds forever and in accordance with which all things come about. He wrote in paradoxes, claiming that the universe is both divisible and indivisible, generated and ungenerated, mortal and immortal, Father and Son, etc... If Xenophanes, in his style of argument, resembled modern professional philosophers, Heraclitus was much more like the popular modern idea of the philosopher as guru. He had nothing but contempt for his philosophical predecessors. Much learning, he said, does not teach a man sense; otherwise it would have taught Hesiod and Pythagoras and Xenophanes. 24  Among Heraclitus’ best-known sayings are these: The way up and the way down is one and the same. Hidden harmony is better than manifest harmony. War is the father of all and the king of all; it proves some people gods, and some people men; it makes some people slaves, and some people free. A dry soul is wisest and best. For souls it is death to become water. A drunk is a man led by a boy. Gods are mortal, humans immortal, living their death, dying their life. The soul is a spider and the body is its web 25  In Heraclitus’ cosmology fire has the role which water had in Thales and air had in Anaximenes. The world is an ever-burning fire: all things come from fire and go into fire; ‘all things are exchangeable for fire, as goods are for gold and gold for goods’. There is a downward path, whereby fire turns to water and water to earth, and an upward path, whereby earth turns to water, water to air, and air to fire. The death of earth is to become water, and the death of water is to become air, and the death of air is to become fire. There is a single world, the same for all, made neither by god nor man; it has always existed and always will exist, passing, in accordance with cycles laid down by fate, through a phase of kindling, which is war, and a phase of burning, which is peace. 26  PARMENIDES The philosophical scene is very different when we turn to Parmenides, who was born in the closing years of the sixth century. Though probably a pupil of Xenophanes, Parmenides spent most of his life not in Ionia but in Italy, in a town called Elea, seventy miles or so south of Naples. He is said to have drawn up an excellent set of laws for his city; but we know nothing of his politics or political philosophy. In his writing he devoted himself not to cosmology, like the early Milesians, nor to theology, like Xenophanes, but to a new and universal study which embraced and transcended both: the discipline which later philosophers called ‘ontology’. Ontology gets its name from a Greek word which in the singular is ‘on’ and in the plural ‘onta’: it is this word – the present participle of the Greek verb ‘to be’ – which defines Parmenides’ subject matter. His remarkable poem can claim to be the founding charter of ontology. 27  as a part of the major branch of philosophy known as metaphysics, ontology often deals with questions concerning what entities exist or may be said to exist and how such entities may be grouped, related within a hierarchy, and subdivided according to similarities and differences. 28  Some philosophers, notably in the traditions of the Platonic school, contend that all nouns (including abstract nouns) refer to existent entities. Other philosophers contend that nouns do not always name entities, but that some provide a kind of shorthand for reference to a collection either of objects or of events. In this latter view, mind, instead of referring to an entity, refers to a collection of mental events experienced by a person; society refers to a collection of persons with some shared characteristics, and geometry refers to a collection of specific kinds of intellectual activities. Between these poles of realism and nominalism stand a variety of other positions. Principal questions of ontology include: "What can be said to exist?" "What is a thing?" "Into what categories, if any, can we sort existing things?" "What are the meanings of being?" "What are the various modes of being of entities?" 29  Empedocles Empedocles flourished in the middle of the fifth century and was a citizen of the town on the south coast of Sicily which is now Agrigento. He is reputed to have been an active politician, an ardent democrat who was offered, but refused, the kingship of his city. In later life he was banished and practiced philosophy in exile. He was renowned as a physician, but according to the ancient biographers he cured by magic as well as by drugs, and he even raised to life a woman thirty days dead. In his last years, he came to believe that he was a god, and met his death by leaping into the volcano Etna to establish his divinity. 30  Empedocles’ philosophy of nature can be regarded as a synthesis of the thought of the Ionian philosophers. As we have seen, each of them had singled out some one substance as the basic stuff of the universe: for Thales it was water, for Anaximenes air, for Xenophanes earth, for Heraclitus fire. For Empedocles, all four of these substances stood on equal terms as the basic elements of the universe. These elements have always existed, he believed, but they mingle with each other in various proportions to produce the furniture of the world. 31  The interweaving and intermingling of the elements, in Empedocles’ system, is caused by two forces: Love and Strife. Love combines the elements together, making one thing out of many things, and Strife forces them apart, making many things out of one. History is a cycle in which sometimes Love is dominant, and sometimes Strife. Under the influence of Love, the elements unite into a homogeneous and glorious sphere; then, under the influence of Strife, they separate out into beings of different kinds. All compound beings, such as animals and birds and fish, are temporary creatures which come and go; only the elements are everlasting, and only the cosmic cycle goes on for ever. 32  THE ATOMISTS Democritus was the first significant philosopher to be born in mainland Greece: he came from Abdera, in the north-eastern corner of the country. He was a pupil of one Leucippus, about whom little is known. The fundamental tenet of Democritus’ atomism is that matter is not infinitely divisible. According to atomism, if we take any chunk of any kind of stuff and divide it up as far as we can, we will have to come to a halt at some point at which we will reach tiny bodies which are indivisible. The argument for this conclusion seems to have been philosophical rather than experimental. 33  Democritus believed that atoms are too small for human senses to detect, they are infinitely many, they come in infinitely many varieties, and that they have always existed. They float in a vacuum, which he called the “void", and they vary in form, order, and posture. Some atoms, he maintained, are convex, others concave, some shaped like hooks, and others like eyes. They are constantly moving and colliding into each other. Democritus wrote that atoms and void are the only things that exist and that all other things are merely said to exist by social conventions. 34  When atoms approach or collide or entangle with each other, the aggregates appear as water or fire or plants or humans, but all that really exists are the underlying atoms in the void. In particular, the qualities perceived by the senses are mere appearances. Democritus’ most often quoted dictum was: By convention sweet and by convention bitter; by convention hot, by convention cold, by convention color: in reality atoms and void. 35  Critics of Democritus complained that while he explained everything else in terms of the motion of atoms, he had no explanation of this motion itself. Others, in his defense, claimed that the motion was caused by a force of attraction whereby each atom sought out similar atoms. But an unexplained attraction is perhaps no better than an unexplained motion. 36  MEANING OF PHILOSOPHY The word philosophy is derived from the Greek words philia (love) and sophia (wisdom) and means “the love of wisdom.” Pythagoras was said to have been the first man to call himself a philosopher; in fact, the world is indebted to him for the word philosopher. It is said that when Leon, the tyrant of Philius, asked him of who he was, he said, “a Philosopher” and he likened the Philosopher to spectators at ancient games. Before that time the wise men had called themselves a sage, which was interpreted to mean those who know. Pythagoras was more modest. He coined the word philosopher, which he defined as one who is attempting to find out. According to him, men and women of the world could be classified into 3 groups: 1. those that love pleasure 2. those that love activity and 3. those that love wisdom. 37  In the loose sense (popular sense) of the term philosophy can be defined as beliefs, opinions, ideologies, perspectives, thinking etc. In the strict sense (academic sense) of the term, Philosophy is the rational attempt to formulate, understand, and answer fundamental questions. It is a rational, critical and systematic inquiry to the underlying thought and experience of human being. Philosophy is the study of general and fundamental problems, such as those connected with existence, knowledge, values, reason, mind, and language. 38  Nature of philosophy Philosophy is a set of views or beliefs about life and the universe, which are often held uncritically. We refer to this meaning as the informal sense of philosophy or “having” a philosophy. Usually when a person says “my philosophy is…” he or she is referring to an informal personal attitude to whatever topic is being discussed 39  Philosophy is a process of reflecting on and criticizing our most deeply held conceptions and beliefs. These two senses of philosophy— “having” and “doing”— cannot be treated entirely independent of each other, for if we did not have a philosophy in the formal, personal sense, then we could not do a philosophy in the critical, reflective sense. Having a philosophy, however, is not sufficient for doing philosophy. A genuine philosophical attitude is searching and critical; it is open-minded and tolerant—willing to look at all sides of an issue without prejudice. To philosophize is not merely to read and know philosophy; there are skills of argumentation to be mastered, techniques of analysis to be employed, and a body of material to be appropriated such that we become able to think philosophically. 40  Philosophy is a rational attempt to look at the world as a whole. Philosophy seeks to combine the conclusions of the various sciences and human experience into some kind of consistent world view. Philosophers wish to see life, not with the specialized slant of the scientist or the businessperson or the artist, but with the overall view of someone cognizant of life as a totality. 41  Philosophy is the logical analysis of language and the clarification of the meaning of words and concepts. Certainly this is one function of philosophy. In fact, nearly all philosophers have used methods of analysis and have sought to clarify the meaning of terms and the use of language. Some philosophers see this as the main task of philosophy, and a few claim this is the only legitimate function of philosophy. 42  Philosophy is a group of perennial problems that interest people and for which philosophers always have sought answers. Philosophy presses its inquiry into the deepest problems of human existence. Some of the philosophical questions raised in the past have been answered in a manner satisfactory to the majority of philosophers. Many questions, however, have been answered only tentatively, and many problems remain unsolved. What is truth? What is the distinction between right and wrong? What is life and why am I here? Why is there anything at all? 43  SOME NOTABLE PHILOSOPHERS Aristotle Ibn-Sina Plato I. Kant Descartes I. Kant Hegel 44  BRANCHES OF PHILOSOPHY Historically, philosophical concerns have been treated under these broad categories: 1. Logic 2. Metaphysics 3. Epistemology 4. Axiology 45  Logic is the systematic study of the rules for the correct use of reasons, rules we can use to distinguish good arguments from bad ones. Most of the great philosophers from Aristotle to the present have been convinced that logic permeates all other branches of philosophy. The ability to test arguments for logical consistency, understand the logical consequences of certain assumptions, and distinguish the kind of evidence a philosopher is using are essential for “doing” philosophy. 46  Another traditional branch of Philosophy traditionally known as metaphysics. For Aristotle, the term metaphysics meant “first philosophy,” discussion of the most universal principles; later the term came to mean “comprehensive thinking about the nature of things.” It means, usually, the study or theory of reality. The question of metaphysics is: what is reality? What is real? Is reality some kind of “thing”. Is it one or is it many? If it is one, then how is it related to many things around us? Can ultimate reality be grasped by five senses, or is it supernatural or transcendent? Metaphysics attempts to offer a comprehensive view of all that exists. It is concerned with such problems as the relation of mind to matter, the nature of change, the meaning of “freedom,” the existence of God, and the belief in personal immortality. 47 The technical term for the theory of knowledge is epistemology, which comes from the Greek word episteme, meaning “knowledge.” In general, epistemology is the branch of philosophy that studies the sources, nature, and validity of knowledge. There are three central questions in this field: (1) What are the sources of knowledge? Where does genuine knowledge come from or how do we know? This is the question of origins. (2) What is the nature of knowledge? Is there a real world outside the mind, and if so can we know it? This is the question of appearance versus reality. (3) Is our knowledge valid? How do we distinguish truth from error? This is the question of the tests of truth, of verification. 48  Traditionally, most of those who have offered answers to these questions can be placed in one of two schools of thought—rationalism or empiricism. The rationalists hold that human reason alone can discover the basic principles of the universe. The empiricists claim that all knowledge is ultimately derived from sense experience and, thus, that our knowledge is limited to what can be experienced. It should be clear that there is a necessary relation between metaphysics and epistemology. Our conception of reality depends on our understanding of what can be known. Conversely, our theory of knowledge depends on our understanding of ourselves in relation to the whole of reality. 49  Axiology is the branch of philosophy that studies values. It can be subdivided into ethics, aesthetics, and social and political philosophy. In broad terms ethics concerns itself with the question of morality. What is right and what is wrong in human relations? Within morality and ethics there are three major areas: descriptive ethics, normative ethics, and metaethics. Descriptive ethics seeks to identify moral experience in a descriptive way. We seek to identify, within the range of human conduct, the motives, desires, and intentions as well as overt acts themselves. 50  Descriptive ethics consider the conduct of individuals, or personal morality; the conduct of groups, or social morality; and the culture patterns of national and racial groups. A second level of inquiry is normative ethics (what ought to be). Here philosophers try to work out acceptable judgments regarding what ought to be in choice and value. “We ought to keep our promises” and “you ought to be honorable” are examples of normative judgments— of the moral ought, the subject matter of ethics. Third, there is the area of critical or metaethics. Here interest is centered on the analysis and meaning of the terms and language used in ethical discourse and the kind of reasoning used to justify ethical statements. Metaethics does not propound any moral principle or goal, but rather consists entirely of philosophical analysis. What is the meaning of “good?” and Can ethical judgments be justified? are typical problems for metaethics. 51  Aesthetics is a branch of philosophy dealing with the nature of beauty and taste. It looks at subjective and sensori-emotional values, which are commonly referred to as judgment of sentiment and taste. Both natural and artificial factors can influence aesthetic perception and judgment. Aesthetics studies about what goes on in our mind when we engage with aesthetic objects or situations like as looking at art, listening to music, appraising poems, seeing a play, or experiencing nature. The study of how artists envision, create, and perform works of art, as well as how others use, appreciate, and evaluate art, is known as aesthetics. Aesthetics studies why some people adore certain works of art while others despise them, as well as how art may influence our emotions and viewpoints. 52  Social and political philosophy investigates value judgments concerning society, the state, and the individual’s relation to these institutions. The following questions reflect the concerns of social and political philosophy:  Why should individuals live in society?  What social ideals of liberty, rights, justice, equality and responsibility are desirable?  Why should anyone obey any government?  Why should some individuals or groups have political power over others?  What criteria are to be used in determining who should have political power?  What criteria are to be used in determining the scope of political power, and  what rights or freedoms should be immune from political or legal control?  To what positive goals should political power be directed, and what are the criteria for determining this? 53  RELEVANCE OF PHILOSOPHY  The study of Philosophy enables us to think carefully and clearly about important issues.  In studying Philosophy, we learn to take a step back from our everyday thinking and to explore the deeper, bigger question which underpins our thought.  The focus in the study of Philosophy is to learn not what to believe, but how to think.  Studying philosophy sharpens your analytical abilities, enabling you to identify and evaluate the strengths and weaknesses in any position.  It hones your ability to construct and articulate cogent arguments of your own.  It prompts you to work across disciplinary boundaries and to think flexibly and creatively about problems which do not present immediate solutions.  Because philosophy is an activity as much a body of knowledge, it also develops your ability to think and work independently. 54 “We are what we repeatedly do. Excellence, then, is not an act, but a habit.” Aristotle 55  CHAPTER TWO: BASIC CONCEPTS IN ARGUMENT Compiled by : Mohammed z.  CONTENTS DEFINING ARGUMENT NONARGUMENTATIVE PASSAGES INDUCTION AND DEDUCTION EVALUATION OF ARGUMENT 2  WHAT IS AN ARGUMENT? Arguments are composed of one or more premises and a conclusion. Premises are statements in an argument offered as evidence or reasons why we should accept another statement, the conclusion. conclusion is the statement in an argument that the premises are intended to prove or support. so, an argument is a group of statements, one or more of which (called the premises) are intended to prove or support another statement (called the conclusion). A statement is a sentence that can be viewed as either true or false. 3  Four things should be noted about statements. First, a sentence may be used to express more than one statement. For example, the grammatical sentence Roses are red and violets are blue Second, a statement can sometimes be expressed as a phrase or an incomplete clause, rather than as a complete declarative sentence. Consider the sentence With mortgage interest rates at thirty-year lows, you owe it to yourself to consider refinancing your home. (radio ad) Third, not all sentences are statements. Example, questions, proposals exclamations , suggestions are not statements Fourth , statements can be about subjective matters of personal experience as well as objectively verifiable matters of fact. 4  Some sentences that look like nonstatements are actually statements and can be used in arguments Alyssa, you should quit smoking. Don’t you realize how bad that is for your health? Do not read beauty magazines. They will only make you feel ugly. How can we tell when a sentence that looks like a command or suggestion is really an ought imperative? The key question to ask is this: Can we accurately rephrase the sentence so that it refers to what someone should or ought to do? 5  IDENTIFYING PREMISES AND CONCLUSIONS In identifying premises and conclusions, we are often helped by indicator words. Indicator words are words or phrases that provide clues that premises or conclusions are being put forward. Premise indicators indicate that premises are being offered. conclusion indicators indicate that conclusions are being offered. 6  Premise Indicators Since in view of the fact that because as indicated by for judging from on account of given that seeing that considering that inasmuch as as 7  Conclusion Indicators Therefore which shows that thus wherefore Hence this implies that consequently as a result So this suggests that accordingly this being so it follows that we may infer that for this reason that is why 8  Note: the existence of indicators can never be a guarantee for a sentence to be premise or conclusion of an argument. Consider the following examples: I haven’t seen you since high school. You’ve had that jacket for as long as I’ve known you. Thus far everything has been great. It was so cold that even the ski resorts shut down. I wouldn’t mind seeing that movie again. There is water on the floor because the sink overflowed. it’s so important to consider the context when determining the meaning of an expression. 9  Sometimes arguments may contain no indicator words. Consider the example below I can’t be completely responsible for my life. After all, there are many factors outside my control, people and forces that create obstacles and undermine my efforts. And we are subject to pressures and influences from within ourselves: feelings of greed, fear of death, altruistic impulses, sexual compulsions, need for social acceptance, and so on. 10 How can we find the conclusion of an argument when the argument contains no indicator words? Find the main issue and ask yourself what position the writer or speaker is taking on that issue. Look at the beginning or end of the passage; the conclusion is often (but not always) found in one of those places. Ask yourself, “What is the writer or speaker trying to prove?” That will be the conclusion. Try putting the word therefore before one of the statements. If it fits, that statement is probably the conclusion. Try the “because” trick. 11  WHAT IS NOT AN ARGUMENT? five types of non-argumentative discourse that are sometimes confused with arguments: Reports unsupported assertions conditional statements Illustrations explanations 12  Reports The purpose of a report is simply to convey information about a subject. Here is an example of a report: Sweeping changes occurred in demographics, economics, culture, and society during the last quarter of the 20th century. The nation aged, and more of its people gravitated to the Sunbelt. Sprawling “urban corridors” and “edge cities” challenged older central cities as sites for commercial, as well as residential, development. Rapid technological change fueled the growth of globalized industries, restructuring the labor force to fit a “postindustrial” economy. 13  Unsupported Assertions Unsupported assertions are statements about what a speaker or writer happens to believe. Such statements can be true or false, rational or irrational, but they are parts of arguments only if the speaker or writer claims that they follow from, or support, other claims. Here is an example of a series of unsupported assertions: I believe that it is not dying that people are afraid of. Something else, something more unsettling and more tragic than dying frightens us. We are afraid of never having lived, of coming to the end of our days with the sense that we were never really alive, that we never figured out what life was for. 14  Conditional Statements A conditional statement is an if-then statement. Here are examples: If it rains, then the picnic will be canceled. You must speak French if you grew up in Quebec. If at first you don’t succeed, don’t try skydiving. Conditional statements are made up of two basic parts. The first part, the statement(s) following the word if, is called the antecedent. The second part, the statement(s) following the word then, is called the consequent. Conditional statements need not be explicitly in if-then form; in fact, in modern usage, then is usually dropped. For example, the following statements are conditional statements: Should it rain, the picnic will be canceled. In the event of rain, the picnic will be canceled. Peter will graduate, provided he passes Critical Thinking. 15 The relation between conditional statements and arguments may now be summarized as follows: A single conditional statement is not an argument. A conditional statement may serve as either the premise or the conclusion (or both) of an argument. The inferential content of a conditional statement may be re- expressed to form an argument Note : a conditional statement can be re-expressed to from an argument if and only if the antecedent of the conditional is only a necessary condition for the its consequent. 16  Consider the following examples: 1- If Rhode Island were larger than Ohio, and Ohio were larger than Texas, then Rhode Island would be larger than Texas. 2 - If john fails Critical Thinking, he’ll be placed on academic probation. John will fail Critical Thinking. So, john will be placed on academic probation. arguments can be composed entirely of conditional statements: 3 - If Tech scores on this play, I’ll eat my hat. If I eat my hat, I’ll have a bad case of indigestion. So, if Tech scores on this play, I’ll have a bad case of indigestion. The first is not argument , though it contains conditional statement (inference) because the arguer doesn’t assert anything. The second and third examples can be considered as argument because they contain both inference and the statement to be asserted. 17  Necessary and sufficient conditions A condition A is said to be necessary for a condition B, if (and only if) the falsity (/nonexistence /non-occurrence) of A guarantees (or brings about) the falsity (/nonexistence /non-occurrence) of B. A condition A is said to be sufficient for a condition B, if (and only if) the truth (/existence /occurrence) of A guarantees (or brings about) the truth (/existence /occurrence) of B. The relationship between the two conditions must be exactly one of the following four possibilities: 1. The first is a necessary, but not a sufficient, condition for the second; or 2. The first is a sufficient, but not a necessary, condition for the second; or 3. The first is both a necessary and a sufficient condition for the second; or 4. The first is neither a necessary nor a sufficient condition for the second. 18  Exercise Identify which conditions best fits in the following relations 1. Thomas being a father is ______________condition for his being a male parent 2. Ojulu being older than bacha is ______________ condition for balcha being younger than Ojulu. 3. Having a married brother is ______________ condition for being an aunt. 4. Wanting to succeed is ______________ condition for success. 5. Thomas being a male is ______________ condition, for being a father. 6. Being more than 6 feet (183 centimeters) tall is ______________ condition for being 6 feet 3 inches 7. A table's being square is ______________ condition, for its having four sides. 19  Illustrations Illustration is the use of examples to make ideas more concrete and to make generalizations more specific and detailed. Illustrations are intended to provide examples of a claim, rather than prove or support the claim. Here is an example: Whenever a force is exerted on an object, the shape of the object can change. For example, when you squeeze a rubber ball or strike a punching bag with your fist, the objects are deformed to some extent. 20  Explanations Consider the following two statements: Titanic sank because it struck an iceberg. Capital punishment should be abolished because innocent people may be mistakenly executed. An explanation tries to show why something is the case, not to prove that it is the case. Explanations have two parts. The statement that is explained is the explanandum. The statement that does the explaining is the explanans. Thus, in the explanation. In everyday speech, we often use “argument” and “explanation” almost interchangeably. How then does one distinguish arguments from explanations? There are four basic tests. 21 The Common-Knowledge Test, is the statement that the passage seeks to prove or explain a matter of common knowledge? If it is, the passage is probably an explanation rather than an argument. (There’s usually little point in trying to prove something that is already a well-known fact.) The Past-Event Test, is the statement that the passage is seeking to prove or explain an event that occurred in the past? If so, the passage is probably an explanation rather than an argument because it is much more common to try to explain why past events have occurred rather than to prove that they occurred. 22 The Author’s Intent Test, is it the speaker’s or writer’s intent to prove or establish that something is the case—that is, to provide reasons or evidence for accepting a claim as true ? Or is it his intent to explain why something is the case—that is, to offer an account of why some event has occurred or why something is the way it is ? If the former, the passage is an argument; if the latter, the passage is an explanation. The Principle of Charity Test, the principle of charity, as we have seen, requires that we always interpret unclear passages generously and, in particular, that we never interpret a passage as a bad argument when the evidence reasonably permits us to interpret it as not an argument at all. This test often proves helpful when the other tests yield no clear answer. 23  DEDUCTION AND INDUCTION Before we can effectively evaluate an argument, we need to understand what kind of argument is being offered. Traditionally, arguments have been divided into two types: deductive arguments and inductive arguments. It is often said that the difference between deduction and induction is that deduction moves from general premises to particular conclusions, whereas induction moves from particular premises to general conclusions. That, however, is a misconception. Here, for example, is a deductive argument that moves not from general premises to a particular conclusion but from particular premises to a general conclusion: Lincoln was president from 1861 to 1865. (particular premise) So, all persons born during Lincoln’s presidency were born in the nineteenth century. (general conclusion) Here is an example of an inductive argument that moves from general premises to a particular conclusion: All of Stephen King’s previous novels have been good. (general premise) Therefore, Stephen King’s next novel will probably be good. (particular conclusion) 24  Key Differences between Deductive and Inductive Arguments Deductive arguments claim that... Inductive arguments claim that... If the premises are true, then the If the premises are true, then the conclusion must be true. conclusion is probably true. The conclusion follows necessarily The conclusion follows probably from the premises. from the premises. It is impossible for all the premises It is unlikely for the premises to be to be true and the conclusion true and the conclusion false. false. Although it is logically consistent It is logically inconsistent to assert to assert the premises and deny the premises and deny the the conclusion, the conclusion is conclusion; if you accept the probably true if the premises are premises, you must accept the true. conclusion 25 There are three tests that greatly simplify the task of determining whether an argument should be regarded as deductive or inductive: the indicator word test the strict necessity test the common pattern test 26  The Indicator Word Test Just as we use indicator words to signal the assertion of premises or conclusions, we use indicator words to signal when our arguments are deductive or inductive. Deduction indicator words : induction indicator words: certainly Probably it logically follows that one would expect that definitely Likely it is logical to conclude that it is a good bet that absolutely it is plausible to suppose that this logically implies that chances are that conclusively it is reasonable to assume this entails that that odds are that 27  The Strict Necessity Test All deductive arguments claim, explicitly or implicitly, that their conclusions follow necessarily from their premises.. The strict necessity test can be stated as follows: An argument’s conclusion either follows with strict logical necessity from its premises or it does not. If the argument’s conclusion does follow with strict logical necessity from its premises, the argument should always be treated as deductive. If the argument’s conclusion does not follow with strict logical necessity from its premises, the argument should normally be treated as inductive. Consider the following arguments: Alan is a father. Therefore, Alan is a male. (deductive , why?) Jill is a six-year-old girl. Therefore, Jill cannot run a mile in one minute flat. (inductive why?) 28  The Common Pattern Test/typical kinds of arguments Typically inductive arguments : Typically deductive arguments Argument based on prediction, Argument based on definition Argument based on analogy Argument based on An inductive generalization mathematics An argument from authority Syllogism An argument based on signs A causal inference 29 COMMON PATTERNS OF DEDUCTIVE REASONING Five common patterns of deductive reasoning:  hypothetical syllogism  categorical syllogism  argument by elimination/disjunctive syllogism  argument based on mathematics  argument from definition 30  Hypothetical Syllogism A syllogism is a three-line argument, that is, an argument that consists of exactly two premises and a conclusion. A hypothetical syllogism is a syllogism that contains at least one hypothetical or conditional (i.e., if-then ) premise. examples of hypothetical syllogisms: If the Tigers beat the Yankees, then the Tigers will make the playoffs. The Tigers will beat the Yankees. So, the Tigers will make the playoffs. If I want to keep my financial aid, I’d better study hard. I do want to keep my financial aid. Therefore, I’d better study hard. 31  Categorical Syllogism categorical syllogism may be defined as a three-line argument in which each statement begins with the word all, some, or no. two examples: All oaks are trees. All trees are plants. So, all oaks are plants. Some Democrats are elected officials. All elected officials are politicians. Therefore, some Democrats are politicians. Because categorical reasoning like this is such a familiar form of rigorous logical reasoning, such arguments should nearly always be treated as deductive. 32  Argument by Elimination An argument by elimination seeks to logically rule out various possibilities until only a single possibility remains. Here are two examples: Either Joe walked to the library or he drove. But Joe didn’t drive to the library. Therefore, Joe walked to the library. Because the aim of such arguments is to logically exclude every possible outcome except one, such arguments are always deductive. 33  Argument Based on Mathematics Mathematics is a model of logical, step-by-step reasoning. Mathematicians don’t claim that their conclusions are merely likely or probable. They claim to prove their conclusions on the basis of precise mathematical concepts and reasoning. In an argument based on mathematics, the conclusion is claimed to depend largely or entirely on some mathematical calculation or measurement (perhaps in conjunction with one or more nonmathematical premises). Light travels at a rate of 186,000 miles per second. The sun is more than 93 million miles distant from the earth. Therefore, it takes more than eight minutes for the sun’s light to reach the earth. 34  Argument from Definition In an argument from definition , the conclusion is presented as being “true by definition,” that is, as following simply by definition from some key word or phrase used in the argument. Here are two examples: Janelle is a cardiologist. Therefore, Janelle is a doctor. Bertha is an aunt. It follows that she is a woman. Because a statement that follows by definition is necessarily true if the relevant definition is true, arguments from definition are always deductive 35  COMMON PATTERNS OF INDUCTIVE REASONING six common patterns of inductive reasoning: inductive generalization predictive argument argument from authority causal argument statistical argument argument from analogy 36  An inductive generalization An inductive generalization is an argument in which a generalization is claimed to be probably true based on information about some members of a particular class. Here are two examples: All dinosaur bones so far discovered have been more than sixty-five million years old. Therefore, probably all dinosaur bones are more than sixty-five million years old. Six months ago I met a farmer from Iowa, and he was friendly. Four months ago I met an insurance salesman from Iowa, and he was friendly. Two months ago I met a dentist from Iowa, and she was friendly. I guess most people from Iowa are friendly. Because all inductive generalizations claim that their conclusions are probable rather than certain, such arguments are always inductive. 37  Predictive Argument A prediction is a statement about what may or will happen in the future. In a predictive argument, a prediction is defended with reasons. Predictive arguments are among the most common patterns of inductive reasoning. Here are two examples: It has rained in Vancouver every February since weather records have been kept. Therefore, it will probably rain in Vancouver next February. Most U.S. presidents have been tall. Therefore, probably the next U.S. president will be tall. Because nothing in the future is absolutely certain, arguments containing predictions are usually inductive. It should be noted, however, that predictions can be argued for deductively. 38  Argument from analogy is a type of inductive argument, whereby perceived similarities are used as a basis to infer some further similarity that has yet to be observed.. Structure : P and Q are similar in respect to properties a, b, and c. P has been observed to have further property x. Therefore, Q probably has property x also. Strength of argument based on authority based on: The relevance of the known similarities to the similarity inferred in the conclusion. The degree of relevant similarity (or dissimilarity) between the two objects. The amount and variety of instances that form the basis of the analogy 39  Causal Argument A causal argument asserts or denies that something is the cause of something else. Here are three examples: I can’t log on. The network must be down. Rashid isn’t allergic to peanuts. I saw him eat a bag of peanuts on the flight from Dallas. It cannot be assumed, however, that causal arguments are always inductive. The following causal argument, for example, is clearly deductive: Whenever iron is exposed to oxygen, it rusts. This iron pipe has been exposed to oxygen. Therefore, it will rust. 40  Statistical Argument A statistical argument rests on statistical evidence—that is, evidence that some percentage of some group or class has some particular characteristic. Doctor to patient: Studies show that condoms have an annual failure rate of 2 to 3 percent, even if they are used consistently and correctly. So, you should not assume that condoms will provide complete protection from the risk of pregnancy or sexually transmitted diseases. Because statistical evidence is generally used to support claims that are presented as probable rather than certain, statistical arguments are usually inductive. 41  Argument from authority An argument from authority , also called an appeal to authority, or argumentum ad verecundiam, is a form of argument in which the opinion of an authority on a topic is used as evidence to support an argument Structure : Person A claim that X is true. Person A are experts in the field concerning X. Therefore, X should be believed. 42  EVALUATION OF ARGUMENTS In the proper sense of the term, an argument can’t be evaluated as god /bad, right/wrong, correct/incorrect, acceptable /inacceptable etc. we have got distinct terminologies to employ to evaluate arguments. Namely : Terminologies to evaluate deductive argument : valid, invalid, sound and unsound. Terminologies to evaluate to inductive argument : strong, weak, cogent and unguent. 43  Valid Deductive Argument valid deductive argument is an argument in which it is impossible for all the premises to be true and the conclusion false. Put another way, a valid deductive argument (or valid argument for short) is an argument in which these conditions apply: If the premises are true, the conclusion must be true. The conclusion follows necessarily from the premises. The premises provide logically conclusive grounds for the truth of the conclusion. It is logically inconsistent to assert all the premises as true and deny the conclusion. 44  Note: truth value is not important for identifying validity. Consider the following argument forms: All adlers are bobkins. All bobkins are crockers. Therefore, all adlers are crockers. All A are B. All B are C. valid If P then Q P valid So, All A are C. so, Q All A are B. If P then Q All C are B. invalid Q invalid So, All A are C. So, P 45  VALIDITY DOESN’T REQUIRE TRUTH VALUE ! 46  some valid arguments have false premises and a false conclusion. For example: All squares are circles. All circles are triangles. Therefore, all squares are triangles. Some valid arguments have false premises and a true conclusion. For example: All fruits are vegetables. Spinach is a fruit. Therefore, spinach is a vegetable. And some valid arguments have true premises and a true conclusion. For example: If you’re reading this, you are alive. You are reading this. Therefore, you are alive. There is, however, one combination of truth or falsity that no valid argument can have. No valid argument can have all true premises and a false conclusion. 47  Invalid Deductive Argument A deductive argument in which the conclusion does not follow necessarily from the premises is said to be an invalid deductive argument. Here are four examples: True premise true conclusion All dogs are animals. Lassie is an animal. Therefore, Lassie is a dog. True premise false conclusion If I’m a monkey’s uncle, then I’m a primate. I’m not a monkey’s uncle. So, I’m not a primate. False premise true conclusion All pears are vegetables. All fruits are vegetables. Therefore, all pears are fruits. False premise false conclusion All dogs are cats. All cats are whales. Therefore, all whales are dogs. 48 Sound argument = valid + all true premise Unsound argument = if at least one of the above conditions is missed. 49  Strong Inductive Argument the conclusion follows probably from the premises. Put otherwise, a strong inductive argument is an argument in which the following conditions apply: If the premises are true, the conclusion is probably true. The premises provide probable, but not logically conclusive, grounds for the truth of the conclusion. The premises, if true, make the conclusion likely. 50  NOTE THAT : LIKE VALIDITY, STRENGTH DOESN’T REQUIRE TRUTH VALUE. 51  Some strong arguments have false premises and a probably false conclusion. For example: All previous U.S. vice presidents have been women. Therefore, it is likely that the next U.S. vice president will be a woman. Some inductively strong arguments have false premises and a probably true conclusion. For example: Every previous U.S. president has been clean-shaven. So, the next U.S. president probably will be clean-shaven. And some inductively strong arguments have true premises and a probably true conclusion. For example: No previous U.S. president has been a native Alaskan. So, the next U.S. president probably will not be a native Alaskan. As with valid deductive arguments, no strong inductive argument can have true premises and a probably false conclusion. 52  Weak Inductive Arguments, like invalid deductive arguments, can have any combination of truth or falsity in the premises and conclusion. Here are some examples: True premise and probably true conclusion Most U.S. presidents have been married. Therefore, probably the next U.S. president will be a man. True premise and probably false conclusion Most U.S. presidents have been over fifty years old. Therefore, probably the next U.S. president will be single. False premise and probably true conclusion Most U.S. presidents have been women. Therefore, probably the next U.S. president will be married. False premise and probably false conclusion Most U.S. presidents have been less than 5 feet tall. Therefore, probably the next U.S. president will be single. 53 Cogent argument : an argument both inductively strong and has all true premises. unguent argument= an inductive argument which is either weak or has at least one false premise. 54  CHAPTER THREE LOGIC AND LANGUAGE Compiled by: Logic Chapter three : Mohammed Z. and Language  “To construct, analyze, and evaluate arguments well, one must pay close attention to language. Many errors of logic stem from a careless or imprecise use of language, and many misunderstandings about logic stem from misunderstandings about the nature of language.” L. Wittgenstein 2 Chapter three : Logic and Language  OUTLINE Functions of languages Types of definitions Techniques of definition Criteria for lexical definitions 3 Chapter three : Logic and Language  Functions of language we take our language for granted. Seldom do we give careful and proper attention to use and application of language. With language : we plan the day’s events, curse the television, exclaim our surprise or frustration (“Damn!”), express pain (“Ouch!”), scribble reminders on scraps of paper, record our thoughts and feelings in diaries and journals, recall past conversations and events, talk to ourselves in anxious moments, pray, wonder, and worry etc. Thought and language create our world, and so to think critically about the world we must pay careful attention to words—the words we choose. 4 Chapter three : Logic and Language  Principal functions of language: Cognitive function: Terminology that conveys information is said to have cognitive meaning. E.g. The death penalty, which is legal in thirty-six states, has been carried out most often in Georgia; however, since 1977 Texas holds the record for the greatest number of executions. Emotive function: terminology that expresses or evokes feelings is said to have emotive meaning. E.g. The death penalty is a cruel and inhuman form of punishment in which hapless prisoners are dragged from their cells and summarily slaughtered only to satiate the bloodlust of a vengeful public. There are other principal functions of languages which are not common in logic. Namely: directive, performative and phatic. 5 Chapter three : Logic and Language  Two points must be noted with regard to emotive meanings: First, since logic is concerned chiefly with cognitive meaning, it is important that we be able to distinguish and disengage the cognitive meaning of such statements from the sheer emotive meaning. The second point is that we must be able to substantiate value claims with reason and evidence. A value claim is a claim that something is good, bad, right, wrong, or better, worse, more important or less important than some other thing. Note that context often determines the purpose of an utterance. "The room is cool" might be used in different contexts: as informative (an observation), expressive (how one feels at the moment), or directive (to turn on the heat). 6 Chapter three : Logic and Language  Vague and ambiguous expressions. Thinking critically and arguing effectively often depend on recognizing imprecise language. Ambiguous or vague language often interferes with clear thinking. A word is ambiguous if it has more than one meaning. For example, in the statement “He lies in this grave,” the word “lie” might mean either tell a falsehood or be prostrate on a horizontal surface, that is, “lie down.” A word is vague if there are borderline cases in which there is no way to determine whether the word applies. For example, how much does a person have to have in the way of material possessions to count as rich? 7 Chapter three : Logic and Language  Verbal and factual disputes Disputes that arise over the meaning of language are called verbal disputes. The dispute concerns ambiguity or vagueness. Disputes that arise over factual state of matter in the phenomenal world are factual type of disputes 8 Chapter three : Logic and Language  a verbal dispute, which occurs when people appear to disagree on an issue but in actuality have simply not resolved the ambiguity of a key term. Suppose two people were asked the same question: “Is the suspect arrested last night guilty of the crime?” The first person answers, “No, a person is innocent until proven guilty.” The second person disagrees: “I say he is guilty; he confessed when he was picked up.” There is really no disagreement here on whether the suspect committed the crime; the first person is defining guilt in a legal sense (the suspect hasn’t been convicted yet), and the second is defining it to mean that the suspect did the crime of which he or she is accused. If someone claims, without further elaboration, that on average “men are more powerful than women,” we would have no way of assessing the claim because powerful has several meanings; and whereas one of those meanings (physical strength) may be defensible, the others may not be. 9 Chapter three : Logic and Language  A factual dispute, on the other hand, occurs when opponents disagree not over the meanings of words but over the relevant facts. Person A might say, “That man did not commit the crime; he has an alibi.” Person B might respond, “He did commit the crime; I saw him do it. 10 Chapter three : Logic and Language  Classify the following words as vague or ambiguous Rich happy Bank Light Normal Excess Right Sure Mode bald 11 Chapter three : Logic and Language  Identify the ambiguous word or phrase in each argument, and succinctly describe the double meaning involved. 1. People nowadays say they can’t believe in religion. They say they can’t believe in miracles. Is it that they can’t believe or that they don’t want to believe? they believe in the miracles of modern science, don’t they? they do. They believe in vaccines, space-walks, and heart transplants. They believe in fiber optics, laser surgery, and genetic engineering. They can believe in miracles, all right. They just don’t want to believe in religious miracles. 2. We are in the dark because the light bulb burned out. But if we are in the dark, then we are ignorant. Therefore, we are ignorant. 3. john is crazy. He will do anything to get a laugh! Of course, if he is crazy, then he should be put in a mental hospital. So, john should be put in a mental hospital. 4. sacred texts says you need faith, but lots of people disagree with those texts. Unfortunately, these people just aren’t thinking straight. The fact that you go out to your car in the morning shows you have faith it’s going to start. And the fact that you pull out of the driveway shows you have faith the car won’t fall apart on the way to work. Everybody needs faith. 5. A crust of bread is a better than nothing. Nothing is better than love. So, a crust of bread is better than love. 12 Chapter three : Logic and Language  Terms as the ultimate constituent part of an argument A term is a word or group of words that can serve as the subject of a statement. Terms includes nouns and descriptive phrases; it doesn’t include verb, adverb, conjunctions and prepositions. All terms have two folds of meanings: intensional meaning ( connotation), and extensional meaning (denotation). The intensional meaning of a term consists of the attributes that the term connotes, and the extensional meaning consists of the members of the class that the term denotes. 13 Chapter three : Logic and Language  Sometimes the denotation of a term can change radically with the passage of time. Some terms have empty extension, but no term have empty intension. The fact that some terms have empty extension leads us to an important connection between extension and intension—namely, that intension determines extension. The intensional meaning of a term serves as the criterion for deciding what the extension consists of. Terms may be put in the order of increasing intension, increasing extension, decreasing intension, and decreasing extension. A series of terms is in the order of increasing intension when each term in the series (except the first) connotes more attributes than the one preceding it, and vice versa. 14 Chapter three : Logic and Language  Definitions and their purposes A definition is a group of words that assigns a meaning to a word or group of words. Every definition consists of two components parts: definiendum and definiens. The definiendum is the word or group of words being defined. The definiens is the word or group of words that does the defining. 15 Chapter three : Logic and Language  Types of Definition 1. Stipulative definition- 2. lexical definition. 3 precising definition. 4. theoretical definition. 5. persuasive definition 16 Chapter three : Logic and Language  Stipulative Definitions If you’ve ever created a new word or used an old word in an entirely new way, you have provided a stipulative definition; that is, you tell your readers or listeners what it is you mean by the term. A stipulative definition is among the most subjective of definitions because the definition is one you have determined. a stipulative definition cannot be true or false, though it can, of course, be more or less fitting or appropriate. Writers frequently stipulate definitions when they give labels to cultural trends, political movements, schools of thought, and so forth. scientists and technologists often stipulate definitions when they make new discoveries or invent new products. Stipulative definitions rarely create problems unless a writer fails to explain clearly that he or she is coining a new word or using an old word with a new meaning. 17 Chapter three : Logic and Language  Persuasive Definitions Another kind of subjective definition is a persuasive definition, in which an arguer defines a term in an effort to persuade a reader or listener to agree with the arguer’s point of view regarding the thing being defined. Persuasive definitions usually contain emotional appeals and slanted/loaded/charged terms and are often given in arguments over highly charged political and social topics on which people have firm views. Here are two examples: 1. Capital punishment means the state-sanctioned, vengeful murder of helpless prisoners. 2. Capital punishment means the infliction of appropriate punishment on vicious cowards who have no regard for life. Each of these is a slanted, “loaded” definition, whose point is not to provide an objective, neutral definition of capital punishment but to persuade the audience to adopt the speaker’s particular attitude toward the death penalty. Note that persuasive definitions are not intrinsically wrong. There is nothing in an attempt to persuade others. However , if our attitude is somehow immoral and inappropriate, trying to persuade others may leads to punishment, blame, or milder forms of criticism 18 Chapter three : Logic and Language  Lexical Definitions Less personal definitions include lexical definitions and precising definitions. In a lexical definition, a word is defined in the way it is standardly used in the language. In other words, the purpose of a lexical definition is to state the conventional, dictionary meaning of a word. Here are two examples: 1. Pastel means a color having a soft, subdued shade. 2. Rug means a heavy fabric used to cover a floor. The second definition accurately states how most people in the United States define rug. In England, however, rug can also mean a type of blanket used to cover the legs while a passenger sits in a car or train. Notice that the definition of rug reflects its general usage, not one person’s use of the word. 19 Chapter three : Logic and Language  precising definition A precising definition is intended to make a vague word more precise so that the word’s meaning is not left to the interpretation of the reader or listener. Here are two examples: 1. From a class syllabus: “Class participation” means attending class, listening attentively, answering and asking questions, and participating in class discussions. 2. A “heavy smoker,” for purposes of this clinical trial, is anyone who smokes more than twenty-four cigarettes per day. In general usage, terms like class participation and heavy smoker are vague. In these examples, they are given comparatively precise meanings to permit clearer understanding and more accurate assessment. 20 Chapter three : Logic and Language  Theoretical Definitions The term theory has several meanings, two of which concern us here. In one sense, theory refers to a general approach to, or belief about, some subject matter that is expressed in a set of interrelated statements concerning the nature of the subject. In this sense, we can speak of a theory of justice. A theory of justice might include such statements as “Justice requires that all persons be treated similarly under similar circumstances,” “Justice requires that individuals in a society be given equal opportunities and access to the good things in that society,” or “Justice demands that punishments should be tailored to the nature of the offense. A second sense of theory refers to scientific theories—that is, to sets of general, but not vague, interrelated statements about the nature of society or the physical world that are subject to testing and proof. 21 Chapter three : Logic and Language  Frequently, scientists take a term from ordinary language, or from another theory, and redefine it for some new theoretical purpose. theoretical definitions are similar to precising definitions in that both reduce vagueness. However, in addition to reducing vagueness, theoretical definitions connect the term being defined with other terms in the theory. Two things must be noted about theoretical definition: firstly, they have got deeper and wider meaning as compared to lexical one. Secondly, is they are interrelated statements about the subject matter being discussed. 22 Chapter three : Logic and Language  Definitional strategies/techniques There are two types of techniques : intensional and extensional. Extensional (Denotative) techniques An extensional definition is one that assigns a meaning to a term by indicating the members of the class that the definiendum denotes. 23 Chapter three : Logic and Language  Ostensive Definitions Sometimes the simplest way to explain the meaning of a word is to give an ostensive definition, which consists in simply pointing to, or demonstrating, the thing being defined. Here are two examples: 1. Door means this. (as you point to one for the benefit of a foreign visitor) 2. Obelisk means this as you point to an obelisk means this! (as you demonstrate to a particular obelisk) Ostensive definitions are often useful (indeed indispensable) in various contexts, but they have obvious limitations. 24 Chapter three : Logic and Language  Enumerative Definitions Another simple way to clarify what you mean by a word is to use an enumerative definition, that is, to provide specific examples of what the word refers to. For example, to help someone understand the meaning of baseball player, you might list some famous baseball players: Babe Ruth, Joe DiMaggio, and Mickey Mantle. To define river you could mention the Nile, the Mississippi, the Thames, and so forth. The trouble with enumerative definitions is that they tend to be incomplete, and hence may give rise to misunderstandings or convey only a very limited understanding of what the word means. For example, your list of baseball players might give the impression that baseball player is synonymous with Yankee. Sometimes it is possible to provide a complete list of a word’s referents (Low Countries means Belgium, Luxembourg, and the Netherlands), but even these may not be very useful if the reader or listener is unfamiliar with the things being enumerated (Diencephalon means thalamus, hypothalamus, epithalamus, and 25 ventral thalamus) Chapter three : Logic and Language  Definitions by Subclass A definition by subclass assigns a meaning to a word by listing subclasses of the general class to which the word refers. Two examples: 1. Mammal means gorilla, horse, lion, whale, and so forth. 2. Poem means sonnet, limerick, haiku, epic, ode, and the like. Definitions by subclass are similar to definitions by enumeration in that both attempt to clarify the meaning of a word by illustrating what the word refers to; however, whereas definitions by enumeration list individual things signified by a word, definitions by subclass list entire classes or categories. Although often helpful, definitions by subclass suffer from the same shortcomings as definitions by enumeration. They can give rise to misunderstandings (our list of mammals might lead someone to think all mammals are large), and they are helpful only if one is broadly familiar with the classes that are named. 26 Chapter three : Logic and Language  Intensional (Connotative) techniques An intensional definition is one that assigns a meaning to a word by indicating the qualities or attributes that the word connotes. There are at least four kinds of intensional definitions: synonymous definition, etymological definition, operational definition, and definition by genus and difference. 27 Chapter three : Logic and Language  Synonymous Definitions A synonymous definition assigns a meaning to a word by offering a synonym—that is, another word that has the same meaning as the word being defined. Two examples: 1. Loquacious means talkative. 2. Deleterious means harmful. Synonymous definitions can be helpful in many contexts. The confusion caused by technical jargon, for example, can be lessened if the jargon is accompanied by a synonymous definition. A trainer carpenter might be puzzled to hear about a chisel’s “bezel” until he or she discovers that the bezel is more commonly known as the “bevel” or even more commonly as the “edge,” or imprecisely as the “point.” Speaking among themselves, teachers might use words like “assessment” or “inventory.” When speaking to parents, teachers might refer instead to “tests.” 28 Chapter three : Logic and Language  Etymological definition A good dictionary tells what part of speech a word is, how it is commonly pronounced, and whence it came—its ancestry, or etymology. Because the meaning of words can change over time, knowing a word’s etymology is quite useful. Etymological definition helps us define the word correctly and use it properly. For example, some people say “ambivalent” when they really mean to say “apathetic” (unconcerned). Ambivalent comes from the Latin word for “both” ( ambi -) and “vigor” ( valentia ); so, to be ambivalent is to feel strongly both ways. Apathy comes from the Latin prefix a, meaning “not,” and from the Greek pathos, meaning “suffering” or, more common, “feeling.” So, to be apathetic is to lack feeling. You might feel ambivalent about abortion, but you are probably not 29 apathetic about it. Chapter three : Logic and Language  Etymological definitions have special importance for at least two reasons. The first is that the etymological definition of a word often conveys the word’s root meaning or seminal meaning from which all other associated meanings are derived. The second reason for the importance of etymological definitions is that if one is familiar with the etymology of one English word, one often has access to the meaning of an entire constellation of related words. 30 Chapter three : Logic and Language  operational definition An operational definition assigns a meaning to a word by specifying certain experimental procedures that determine whether or not the word applies to a certain thing. Examples: 1. One substance is ‘‘harder than’’ another if and only if one scratches the other when the two are rubbed together. 2. A subject has ‘‘brain activity’’ if and only if an electroencephalograph shows oscillations when attached to the subject’s head. 3. A ‘‘potential difference’’ exists between two conductors if and only if a voltmeter shows a reading when connected to the two conductors. 4. A solution is an ‘‘acid’’ if and only if litmus paper turns red when dipped into it. 31 Chapter three : Logic and Language  Operational definitions are invented in an attempt to understand abstract concepts on the basis of empirical ground and experimental evidences. They are successful, in some respect. Operational definition has got two limitation: Firstly, operational definitions usually convey only part of the intensional meaning of a term. Certainly ‘‘brain activity’’ means more than oscillations on an electroencephalograph, just as ‘‘acid’’ means more than blue litmus paper turning red. Secondly, applying operational definition outside the framework of science is severely difficult and impossible. Words as ‘‘love,’’ ‘‘respect,’’ ‘‘freedom,’’ and ‘‘dignity.’’ cant be defined operationally. 32 Chapter three : Logic and Language  Definition by Genus and Difference One of the most useful strategies for defining terms is to define by genus and difference, a method that lexicographers (dictionary writers) often use to create definitions. A definition by genus and difference assigns a meaning to a word by identifying a general class (genus) to which things named by the word belong and then specifying a differentiating quality (difference) that distinguishes those things from all other things in the class. Two examples: 1. Buck means male deer. 2. Calf means young cow. 33 Chapter three : Logic and Language  The ‘‘specific difference,’’ or ‘‘difference,’’ for short, is the attribute or attributes that distinguish the various species within a genus. It should be noted that one limitation of the genus and difference method is that it can be used to define a word without capturing the true essence of the thing that is defined. Definition by genus and difference is the most effective of the intensional definitions for producing the five kinds of definitions. 34 Chapter three : Logic and Language  Criteria for Lexical Definitions Rule1: A Lexical Definition Should Conform to the Standards of Proper Grammar Rule2: A Lexical Definition Should Convey the Essential Meaning of the Word Being Defined Rule 3: A Lexical Definition Should Be neither Too Broad nor Too Narrow Rule 4: A Lexical Definition Should Avoid Circularity Rule 5: A Lexical Definition Should Not Be Negative When It Can Be Affirmative Rule 6: A Lexical Definition Should Avoid Figurative, Obscure, Vague, or Ambiguous Language Rule 7: A Lexical Definition Should Avoid Affective/slanted/loaded Terminology Rule 8: A Lexical Definition Should Indicate the Context to Which the Definiens Pertains 35 Chapter three : Logic and Language  A lexical definition should conform to the standards of proper grammar the definiendum should be put in quotation marks or italics The definition should clearly state the species, the genus and the differentia. 1. Correct: “Vacation” means a periods during which activity is suspended from work or school 2. Incorrect: Vacation is when you don’t have to go to work or school. The second definition doesn’t clearly state the genus term. So, it is grammatically erroneous. 36 Chapter three : Logic and Language  Don’t make the definition too broad or too narrow. A definition is too broad if it includes too much and is too narrow if it includes too little. A good definition applies to all and only the things being defined. A definition of automobile as “a vehicle with four wheels” would be too broad because it would include golf carts and lawn mowers. A definition of sibling as “brother” would be too narrow because it fails to include sisters. 37 Chapter three : Logic and Language  Don’t make the definition negative when you can make it affirmative A Lexical Definition Should Not Be Negative When It Can Be Affirmative - Of the following two definitions, the first is affirmative, the second negative: 1. ‘‘Concord’’ means harmony. - correct 2. ‘‘Concord’’ means the absence of discord. - incorrect Some words, however, are intrinsically negative. For them, a negative definition is quite appropriate. Examples: 1. ‘‘Bald’’ means lacking hair. 2. ‘‘Darkness’’ means the absence of light. 38 Chapter three : Logic and Language  Convey the essential meaning of the word being defined. A good definition should do more than just pick out some uniquely identifying properties of the thing being defined. Defining horse, for example, as “the animal ridden by Napoleon during the battle of Waterloo” is clearly a poor definition, even though the defining expression does apply uniquely to horses. The problem with the definition is that it fails to capture the really important and necessary properties that make horses horses, rather than, say, cows or sheep. Expressing the essential meaning of a word can be very difficult and often requires specialized knowledge. 39 Chapter three : Logic and Language  Provide a context for ambiguous words. Many words are ambiguous; that is, they have two or more distinct meanings. For example, a “walk” in baseball is different from a “walk” in the park. To prevent confusion, therefore, a good definition should indicate the context in which an ambiguous word is being used. we might say, “‘Walk’ means (in baseball) an award of first base to a batter who receives four pitched balls that are outside the strike zone and are not swung at by the batter.” 40 Chapter three : Logic and Language  Avoid slanted definitions. Don’t let personal preferences or attitudes interfere with your definition. Avoid slanted definitions—that is, biased or emotionally charged definitions that improperly play on the emotions or attitudes of an audience. 41 Chapter three : Logic and Language  Avoid figurative definitions. A good definition should express clearly the conventional meaning of a word, not be couched in figurative or metaphorical language. Consider these examples: 1. Slot machine means one-armed bandit. 2. Advertising means legalized lying. 3. Religion means the flight of the alone to the Alone. “Definitions” such as these may have their place (they may be humorous or clever, for example); but if a straightforward definition is in order, such figurative language should be avoided. 42 Chapter three : Logic and Language  Avoid needlessly obscure definitions. A good definition should clarify the meaning of a word for someone who may be unfamiliar with the term. Thus, a definition should not include a lot of big words or technical jargon that readers aren’t likely to understand. For example: 1. Mouse means a quadrupedal mammalian of any of the more diminutive species of the genus Mus of the order Rodentia. For people not trained in biology, this definition is 43 likely to be more confusing than helpful. Chapter three : Logic and Language  Avoid circular definitions. A circular definition is one that uses the term(s) being defined-definiendum-as a part of the definines with no or little modification. 1. Entomologist means someone who engages in the science of entomology. 2. Gambler means someone who gambles Such definitions are likely to be unhelpful because the defining phrases are just slight variants of the words being defined. 44 Chapter three : Logic and Language  Exercise Match column A with column B Column A 1. ‘‘Pen’’ means an instrument used for writing on paper. 2. ‘‘Triangle’’ means a figure composed of three straight lines in which all the angles are equal to 180. 3. ‘‘Elusory’’ means elusive.. 4. “A theist” is anyone who is not an atheist or an agnostic. 5. “Feminism” is a militant movement originated by a group of deviant women for the purpose of undermining the natural distinction between the sexes. 6. ‘‘Truculent’’ is if you’re cruel or fierce. 7. “A house” is a structure made of wood or stone intended for human habitation. 8. ‘‘Strike’’ means a pull on a line made by a fish in taking the bait. Column B A. Too broad B. Fail to indicate the context C. Toot narrow D. Affective E. negative