BRANCHES OF PHILOSOPHY 3 LOGIC AS A BRANCH

BRANCHES OF PHILOSOPHY 3 - LOGIC AS A BRANCH OF PHILOSOPHY

Why do we study Logic? In our routine life, we pass different judgements. We attempt to justify these judgements by providing grounds. The grounds which we provide may be based upon rational as well as non-rational instruments like, i. Habits. ii. Desires. iii. Feelings and Emotions. iv. Customs and Traditions, and. v. Reason. Note: i, iii, iv are non-rational instruments and v is a rational instrument.

Most Reliable Instrument: When reliable judgements are needed, the instrument we most wisely depend on is “Reason”. In every serious intellectual pursuit we come ultimately to rely on reasoning because there is nothing that can successfully replace it. Humans are endowed by nature with powers of reasoning. Logic is the study of the uses of those powers. In the study of logic we come to recognize our own native capacities, and by exercise we strengthen them. The study of logic helps one to reason well by illuminating the principles of correct reasoning.

Why do we need Correct Reasoning? Correct Reasoning is useful wherever knowledge is sought. Whether in science, politics, or in the conduct of our private lives, we use logic in reaching defensible conclusions. In formal study, we aim to learn how to acquire reliable information and how to evaluate competing claims for truth. The study of logic helps us to identify arguments that are valid or good and the reasons why they are valid or good on one hand. And on the other hand it help us to identify arguments that are invalid or bad and the reasons why they are invalid or bad.

Definition of Logic: Logic is the science of reasoning. Note: Reasoning is the process of drawing inferences from the given information. Logic is the study of methods, techniques and principles used to differentiate correct reasoning from incorrect reasoning. Note: Correct Reasoning is the process of thinking about things in a logical way. Opinions and ideas that are based upon logical thinking. Logic is the study of methods, techniques and principles used to differentiate valid or good arguments from invalid or bad arguments.

What is an Argument? An argument is any group of propositions of which one is claimed to follow from the others, which are regarded as providing support or grounds for the truth of that one. OR An argument is a group or cluster of propositions/statements, in which, one proposition known as the conclusion, is inferred, deduced, induced or derived on the basis of other proposition/s called premise/s. OR An argument is a group of propositions in which one proposition known as the conclusion is supported on the basis of other proposition/s called premise/s.

Continue: Note: Inference: A process of linking propositions by affirming one proposition on the basis of one or more other propositions. Premise: A proposition used in an argument to support some other proposition. Conclusion: The proposition in an argument that the other propositions, i. e. , premises support.

Examples of an Argument: All humans are mortal, Socrates is a human, Therefore, Socrates is mortal. Earth is a planet, It revolves around the sum, Probably all planets revolve around the sun. Pakistan is to the east of Afghanistan; therefore, Afghanistan is to the west of Pakistan.

Proposition: A proposition is an assertion that something is (or is not) the case; all propositions are either true or false. OR A proposition is a declarative sentence which asserts or denies something. A sentence, which can be proved as true or false. A sentence, which gives us some information about some fact. E. g. , Pakistan is situated in South Asia. Pakistan has four Provinces. The capital of Pakistan is Islamabad. The Capital of Afghanistan is Kabul. Electrons revolve around the nucleus. Note: In logic, proposition and statement is used in a synonymous meaning.

Continue: NOTE: Proposition can either be simple or compound in nature. Simple Proposition: A proposition making only one assertion OR A sentence which gives a single information about a single fact. E. g. , Hamlet is written by Shakespeare. Compound Proposition: A proposition containing two or more simple propositions OR A sentence giving more than one information about some fact or one information about more than one facts. E. g. , x is ill and he is admitted in the hospital. x has a corona infection and y also has a corona infection

Types of Arguments: It is the claim of every argument that its premises support its conclusion. An important question can come into our mind, how much support? 100 % support or 1 up-to 99 % support? On the basis of these two possibilities, logicians have divided arguments into two broader categories, i. e. , 1. Deductive Argument, Deductive Reasoning or Deduction. 2. Inductive Argument, Inductive Reasoning or Induction

Deduction: An argument, which claims that its premise/s provide full, absolute, conclusive, certain or 100 % support to justify the conclusion is called deductive argument. It is either valid or invalid. Note: If an argument is successful in its claim, i. e. , premises do provide 100 % support for the conclusion, it is valid, while, it is unsuccessful in its claim, i. e. , premises do not provide 100 % support for conclusion, it is invalid. It moves from general to specific, i. e. , from universal towards particular. Note: According to modern logicians, this is not the necessary feature of a deductive argument to always move from general to specific or particular. A deductive argument can move from general to general or specific to specific even. This was an important characteristic of deduction only according to classical, traditional or Aristotelian logicians. Once a deductive argument is proved to be valid, it cannot be made more valid. Note: Certainty is equal to 100 %.

Examples: All humans are mortal, x is a human, Therefore, x is mortal All Pakistanis are Asians, All Pashtuns are Pakistanis, Therefore, all Pashtuns are Asians. X is greater than Y, Y is greater than Z, therefore, X is greater than Z.

Induction: An argument, which claims that its premises provide only probable rather than certain grounds to justify its conclusion is called inductive argument. It is either good or bad, better or worse, stronger or weaker. Note: The level of probability determines the strength or weakness of an inductive argument. It moves from specific/ particular to general/ universal. Note: Not a necessary feature of induction according to modern logicians. An inductive argument can move from specific to specific even. The probability of an inductive argument can be increased or decreased. Note: By adding relevant and deleting irrelevant premises, probability can be increased, and by adding irrelevant and deleting relevant premises, probability can be decreased. Note: Probability ranges from 1 up-to 99 %.

Examples: Earth is a planet and revolves around the sun, Mars is a planet and revolves around the sun, Probably all planets revolve around the sun. X is a student of English literature and intelligent, Y is a student of English literature and intelligent, Z is also a student of English literature, Probably, Z is also intelligent.

Language: Problems of language, Functions of language. Language is a medium of communication. It is a tool used for instructions. It is a way of expression. It is a source of information. It can be verbal and non-verbal, (spoken, written, gestures, signs and symbols). Note: it is the only medium of communication, we humans have but unfortunately it is not a very good tool due to several reasons. There are many pitfalls rooted in its nature, which can lead us towards confusions and misunderstanding.

Pitfalls or Problems of language: Ambiguity of Words: Words having more than one meanings are ambiguous, when they are used out of their proper context, OR words which are used with more than one meaning are called ambiguous words. E. g. , Bank: Money bank, Blood bank, Book bank, River bank Sharp: Sharp knife, Sharp Time, Sharp person, Sharp edge Resident: Permanent resident, Temporary resident Note: Almost every word in a dictionary has more then one meaning, Can we say that all words are ambiguous then? According to philosophers of language or semantics, words by themselves are not ambiguous, we make the ambiguous, when we use them out side their proper context. Vagueness of words: Words lacking precision are called vague words. Words, whose boundary lines are not clear, i. e. , we are not clear about their applicability and non-applicability limits. All polar words are vague in nature. E. g. , Fast and Slow: The car is running very fast. What do we mean to say when we use the word fast? Do we mean 60 km/h, 100 km/h, 120 km/h or 140 km/h etc. Large and Small, long and Short etc.

Continue: Emotiveness of Words: Words, which can be used for the expression of feelings and emotions with an intention to awoke, provoke, produce or generate the same kind of feelings or emotions in the listeners are called emotive words. Such words are often used for emotional triggering or blackmailing. E. g. , Making an appeal to the emotion of pity, sympathy, anger, love, hatred etc. Psychological Persuasiveness of Words: Words, which can be used for influencing or targeting the minds of the listeners are called psychologically persuasive words. E. g. , The beaten route is the best route, OR All the celebrities smoke; hence smoking is good.

Functions of Language: Important functions of language are the following. 1. Informative Function of Language: A very important function of language is to transfer information from one person to another. E. g. , France is in Europe and China is in Asia. Information: Directly verifiable (Naked eyes) e. g. , The color of snow is white. Indirectly verifiable (Intermediate source between the observer and phenomena under observation like microscope)e. g. , Electrons revolve around the nucleus, or Malaria is caused by a parasite called plasmodium. Verifiable in principle (Verified on the basis of some scientific principle) e. g. , Mass of the earth, Weight of the earth, Fission process on the sun causing a lot of energy, which reach us in the form of heat and light.

Continue: 2. Expressive Function of Language: An important function of language is to express one’s feelings and emotions intending to awoke, provoke, produce or generate the same in listeners. Used in Poetry, Novels, Dramas. E. g. , Poets Used in speeches and debates. E. g. , Politicians It can be public or private. Public: Politicians, An attempt to target the feeling of patriotism. Private: An individual’s own attempt to trigger his/her own emotions during prayer etc. Note: Expressive language is not bad when used in poetry, novel or plays etc. , but it turns bad when we use it in reasoning and argumentation.

Continue: 3. Directive Function of Language: Another important function of language is to give directions, i. e. , Giving commands and Making requests. E. g. , Open the door, Please give me your pen.

Fallacy: A fallacy is an error or mistake in reasoning. A fallacy is a type of an argument which seems to be valid or good in its appearance, but when we analyze it deeply using logical methods or principles, we discover that there is a logical error or mistake in it. This error in an argument can occur because of two reasons; hence, logicians have divided fallacies broadly into two categories. 1. Formal Fallacy: A fallacy which is the result of an incorrect form or structure of an argument is called formal fallacy. It always occur in a deductive argument. E. g. , All A’s are B’s, All C’s are B’s; therefore, all A’s are C’s (All dogs are animals, all cats are animals; therefore, all cats are dogs). 2. Informal Fallacy: A fallacy which is the result of an incorrect content (words, propositions, i. e. , language) of an argument is called informal fallacy. It always occur in an inductive argument. E. g. , The highest form of evolution is man, as woman is not man; therefore, woman is inferior to man. OR Philosophy is an art, art is studied by art historians; therefore, philosophy is studied by art historians.