logic & critical thinking

Introduction To Logic & Critical ThinkingQ.1: What is Logic?ANS: LOGIC: -

Definition No.1: “Logic is the method and principle which enables us to distinguish between correct from incorrect”. Definition No.2: “Logic is simply the study of arguments that man should speak to persuade other with truth correctively’. Definition No.3: “Logic is actually the applicability of minds”.Q.2: What is The History Of Logic?ANS: History of Logic: -

1) According To PROF.MINTO:- To, speak a logic as body of rules for the investigation of truth has misled people into supposing that it claim to be an art of discovery, to lay down rules for arriving at new truth. Logic helps the men on the road to truth.

2) According To PETRARCH (1304 – 1374):- Logic is one of the liberal studies, a ladder for those who are striving upward, and by no mean a useless protection to those who are forcing their ways through the thorny ticket of philosophy. Simply the methods used to distinguish correct from incorrect data.

3) According To ARISTOTLE OF STAGIRA (322 – 384 BC):- Aristotle was the son of “Macedonian physician” at the court of Amyntas-II the father of Philips of Macedon. In Athens Aristotle set up his school or, university called “Lyceum”. The Aristotle of writing on logic includes Prior Analytics (which deals mainly with formal aspects of syllogistic reasoning). Posterior Analytics (which treat of deeper problems of inference and techniques establishing and refuting arguments). To, him for logic is not an end itself, but is mean fitting minds to acquire knowledge in any branch of the science or, humanities.

4) According To JOHN LOCKE (1632-1704):- John Locke said that “God, has not been so sparing to men to make barely two leggedcreatures, and left is to Aristotle to make them rational”. Logic means art of reasoning (correctively) or the ability to argue and convince. The logic comes from Latin words “Loyos” means Discourse. So, logic is still a discipline of discourse.

Q.3: What is The Importance Of Logic?i. The importance of logic helps a man to acquire & retain knowledge and detect a bad argument.

ii. Not, only your thinking but your speaking and writing should show benefits, they should gain clarity, precision, and firmness, the lack of logic show the deficiency of diseases in mind of vagueness, woolliness, of expression.

iii. Consistency in thought, speech, feeling, character, & action is a mark of rationality and fruit of logic.

iv. It make us should better thinker, and reasoner.v. The study of logic help to correct such minor in-accuracies, we learn to break up our sentences into

their component parts. We draw a circle so, to speak. Round our subject. Draw another circle round our predicate. When have dawn those two circle, then, and not till then, we know what we are speaking about and precisely what are saying about it.

vi. Precision is first fruit of logic and precision will sharpen your statement and add points to force

1 Written By : Amir Hassan of Chemistry Deptt Post Graduate Collage Mardan Follow at Google + : [email protected]

Introduction To Logic & Critical Thinkingyour arguments.

vii. It study certainly introduces you to deep question about mind and body to the problems of taught and thing.

Q.4: How you can define Quality in term Of Logic?ANS: Quality: - Every standard from categorical proposition either affirm, or denies some class relation. If the proposition affirms some class, inclusion, whether complete or partial its quality is affirmative.

Generally quality in categorical proposition means to accept or, reject it. Every categorical proposition has one quality.

Affirmative: The A proposition = Latin word mean “affirm”. The I proposition = mean “I affirm”.e.g. 1) All S is P. (Suppose A) 2) Some S is P. (Sure I) These both are affirmative in quality.

Negative: if the proposition denies class inclusion, whether complete or, partial its quality is negative.

The ‘E’ and ‘O’ proposition = Latin word “nEgO” meaning “I deny”. e.g. 1) No S is P. (Sur E) 2) Some S is not P. (Some O)

Q.5: How you can define Quantity in term Of Logic?ANS: Quantity: - Every standard form categorical proposition has some class as its subject. If the proposition refer to all member of the class designated by its subject term its quantity is universal.

i. The quantity of standard form categorical proposition is revealed by the word which begins, “All”, ‘No”, and “Some”.

ii. The “All and No” indicate proposition is universal.iii. The “Some” indicate proposition is particular.

e.g. All S is P. (Suppose A) No S is P. (Sure E)

Q.6: Write a detailed note on Immediate inference?ANS: Immediate Inference: - inference is the transition from data to conclusion act of drawing conclusion from one or, more facts are called inference.

The point from which the inference proceeds is called data. The point to which the inference proceeds is called conclusion. There’re various partial synonyms for term data, inference, conclusion, but from present these

will serve. There is no limit to the range and variety of facts which may be used as data for inference. From the fact that sun has risen so, many times we might infer that it will continue to do so.

Example: A youth comes out of fraternity house, carrying a brief case, walk to the campus, and enter one of the university buildings. From the data i.e. given fact one might infer that he is student.

Kinds Of Immediate Inference: - there are three kinds of immediate inference.


Introduction To Logic & Critical Thinking1) Conversion.2) Obversion.3) Contraposition.

1) Conversion: Conversion is an inference that proceeds by interchanging the subject and predicate term of proposition. e.g. 1) No men are angles. 2) No angles are men.

This proposition may validly infer from one another. The classes and class component should be kept in mind. Every class is associated with it

complementary class which is the collection of all things that don’t belong to original class. The complement of the class is represented by the terms “S” and then represented by term

“non-S”. We may speak of term “non-S” as being the complement of term “S”.

2) Obversion: To, obvert a proposition we change its quality (affirmative to negative or, negative to affirmative) and replace the predicate term with its complement.However, the subject terms remain unchanged and so does the quantity of proposition being obverted. e.g. 1) All residents are voters. (Sure A) 2) No resident are non-voters. (Suppose E)

3) Contraposition: To, form the contrapositive of given proposition its subject term is replaced by or, with complement of its subject term neither the quality nor the quantity of the original proposition is changed.

The contrapositive proposition of “A” is always “A” proposition. The contrapositive proposition of “O” is always “O” proposition Etc. These are logically equivalent proposition as reflection contraposition and valid form of

immediate inference. It really introduces nothing new we can get from any “A” proposition to its contrapositive

by first obverting it, next applying Obversion, and then applying Obversion again.

e.g. 1) All members are voters. 2) All members are non-voters.

IF “P” Then “Q”: An inference may always expressed in the form if “P” then “Q”. Where “P” represented the datawhile “Q” the conclusion, “If” then the inference. When an inference is expressed or, formulatedthere is arguments.

Q.7: Explain The Term Conversion with diagram?ANS: Conversion: -


Introduction To Logic & Critical Thinking “It consists in switching the subject term with the predicate term”.e.g. If statement “No foxes are hedgehogs” is converted resulting statement is “No hedgehogs are foxes”. This new statement is called the converse of the given statement.To, see how four type of categorical proposition relate to their converse compare the set of Venn diagrams:

Given Statement ConverseAll A are B. All B are A.

A B A B

No A are B. No B are A.

A B A B

Some A are B. Some B are A.

A B A B

Some A are not B. Some B are not A.

A B A B

Q.8: Discuss in detail the term Fallacies?ANS: Fallacies: -

Definition No.1: “It’s a type of incorrect arguments, any arguments that does not exhibit that kind of mistake is said to commit that fallacy.” Definition No.2: “When the premises of an argument fail to support its conclusion and argument of that sort may be called fallacies.” Definition No.3: “Any error in reasoning is called fallacy”.Classification Of Fallacies: - they can be classified as the following.


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XAMIR HASSAN Chemsitry DepttSigned by: AMIR HASSAN

Introduction To Logic & Critical Thinking1) Fallacies of Relevance.2) Fallacies of Presumption.3) Fallacies of Ambiguity.

1) Fallacies of Relevance: They are the most numerous and most frequently encountered.In these fallacies the premises of the argument are simply not relevant to the conclusion. However, because they made to appear to be relevant they may deceive.

Types of Fallacies of Relevance: there are eight different types of fallacies.1) The Appeal To Emotion: A fallacy in which every propagandist relies an appeal to the emotion

of audience. The speaker or, writer relies on expressive language & other devices calculate to exciteenthusiasm for some causes.

2) Red Herring Fallacy: A fallacy in which attention is deflected reader or, listener are drawn to some aspects of the topic under discussion by which they led away from the issue that had been the focus of discussion.

3) Straw Man Fallacy: If one argues against some view by presenting an opponent’s position as onethat easily torn apart the argument is fallacious of course.

4) Fallacy of Argument against The Person: In addition to being unfair to the adversary is hurtful often inflecting serious personal damage without any opportunity of the fallacy to be exposed.

5) Fallacy of Argument Abusive: One this temped in heated argument to disparage the character of one’s opponents to deny their intelligence or, reasonableness to question their understanding or, their seriousness or, even their integrity.

6) Fallacy of Argument Circumstial: The mistake made in Circumstial form of the ad hominent fallacy is to treat those personal circumstances as the premise of an opposing argument.

7) Fallacy of Appeal To Force: It mean literal appeal to the stick and is surely is clear however expedient force may prove to be it cannot replace rational methods of arguments.

8) Fallacy of Argument of Missing Point: This fallacy is the product of sloppy thinking confusion in reasoning that the author of the argument herself does not fully recognize or, grasp.


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