Logic Ppt

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Logic Ppt

  1. 1. INTRODUCTION<br />The Study of Logic<br />
  2. 2. Definition<br />Derived from the Greek word ”logos” which means - study, reason or discourse<br />LOGIC is the science and art of correct thinking<br /> - it is a SCIENCE because it is a systematized body of logical truths and principles governing correct thinking<br />
  3. 3. - as an ART, logic is a “techne” and it teaches how to make a good argument<br /> - often called the arts of arts because it develops and perfects the intellect which all artists need in their work<br />
  4. 4. Logic and correct thinking<br />It is “correct” when it conforms to a pattern or to rules<br />Example: A ruler is 12-inch long<br /> Pres. GMA is a ruler<br /> Therefore, Pres. GMA is 12-inch long <br />-THINKING is a mental process – involves analysis, definition, classification, comparison and contrasts, etc.<br />- It guides or directs man to form correct ideas<br />
  5. 5. Branches of logic<br />FORMAL LOGIC<br />-concerned with the aspect of form which has something to do with the correctness or sequence or the following of rules<br />Ex. All men are mortal<br /> but Pedro is a man<br /> therefore Pedro is mortal<br />
  6. 6. Branches of logic<br />MATERIAL LOGIC<br />-concerned with the aspect of subject matter or content or truth of the argument<br />Example: A ruler is 12-inch long<br /> Pres. GMA is a ruler<br /> Therefore, Pres. GMA is 12-inch long<br />KINDS <br /><ul><li>Deductive Logic: from more to less
  7. 7. Inductive Logic: implies a sense of probability</li></li></ul><li>Concepts and terms<br />The three essential operations of the intellect<br />
  8. 8. concept<br />The representation of an object by the intellect through which man understands or comprehends a thing<br />It is an “idea”- starts with an outside reality and apprehended by the senses<br />
  9. 9. Kinds of concept <br />1.First Intention: we understand what the thing is according to what it is in reality<br /> Ex. A dog is an animal.<br />Second Intention: we understand not only what the thing is according to what it is in reality but also how it is in the mind <br /> Ex. “Monte Vista” (Mountain View) is the name of my subdivision<br />
  10. 10. Kinds of concept <br />2.Concrete Concepts: expresses a “form” and a “subject”<br /> Ex. The flower rose<br />Abstract Concepts: has a “form” only , has intangible quality, that which cannot be perceived by the senses<br /> Ex. Beauty in a woman<br />
  11. 11. Kinds of concept <br />3.Absolute Concepts: signifies the meaning of a concept, all definitions are absolute concepts<br /> Ex. A triangle is a three-sided figure.<br />Connotative Concepts: signifies a characteristic existing in the concept, all modifiers are connotative concepts<br /> Ex. Drummer boy<br />
  12. 12. Kinds of concept <br />4.Positive Concepts: signifies the existence or possession of something<br /> Ex. happy<br />Negative Concepts: signifies the absence of something<br /> Ex. sad<br />
  13. 13. Seatwork #2<br />Underline the simple subject of each proposition then classify according to the four kinds of concepts in the column below:<br />Justice is a prerequisite of love.<br />Men are creatures of God.<br />“Freedom” is the name of our park.<br />Honesty is still the best policy.<br />Joy is Zeny’s friend. <br />
  14. 14.
  15. 15. Assignment #2<br />Underline the simple subject of each proposition then classify according to the four kinds of concepts in the column below:<br />1. Love is a many-splendored thing.<br />2. “Love” is the theme of the homily.<br />3. The loving couple is a model to their children.<br />4. Hope is the opposite of despair.<br />5. “Hope” is the street where I live. <br />6. The urban poor are people in need of hope.<br />
  16. 16. The term<br />The external representation of a concept and the ultimate structural element of a proposition.<br /> - external representation means it is always a sign of a concept or an idea<br /> - ultimate structural element means it could either be the subject or predicate of a proposition <br />
  17. 17. The term<br />EXAMPLE:<br />Hilda is a (nun).<br />subject<br />predicate<br />
  18. 18. Properties of a term<br />EXTENSION OF A TERM<br /><ul><li>the sum total of the particulars to which the comprehension of a concept can be applied
  19. 19. The denotation of a term
  20. 20. The terms that are members of the domain of the concept</li></li></ul><li>Properties of a term<br />COMPREHENSION OF A TERM<br /> - the sum total of all notes which constitute the meaning of a concept<br />- set of traits or characteristics that differentiates the term in a group<br />- the connotation of a term<br />
  21. 21. Properties of a term<br />Example is the term BAT<br />-for its extension it will include all animals, regardless of size, shape, colour, or breeding<br />-further analysis (comprehension), know the nature of bats – how?<br />- You must try to state the trait or set of traits and characteristics that differentiates bats from the rest of the animal kingdom<br />
  22. 22. Properties of a term<br />Example is the term BAT<br />-the important common trait of bats is: they are the only mammals capable of sustained flight like a bird <br />- Unlike birds, bats are able to fly at low speed with extreme maneuverability.<br />
  23. 23. RELATIONSHIP<br />Comprehension and Extension are related to each other inversely<br />Meaning: the greater the comprehension of a term, the lesser its extension and vice versa<br /> - the arrangement of the characteristics from general to specific<br />Ex. city, barangay, province, municipality, region, country , sitio<br />
  24. 24. Seatwork#3<br />Arrange the ff. from greater comprehensiont o lesser extension<br />Pedro, Filipino, Man, Asian, Brown Race<br />Square, Plane, Figure, Rectangle, Polygon, Parallelogram, shape<br />
  25. 25. Answer to sw#3<br />1. Man 2. Plane<br /> Asian Figure <br /> Brown Race Shape <br /> Filipino Polygon <br /> Pedro Parallelogram<br /> Rectangle<br /> Square<br />
  26. 26. Quantities of terms<br />SINGULAR – it stands for a single definite individual or group<br /> - Proper nouns ex. Raul, La Union, DMMMSU<br /> - Nouns modified by adjective to the superlative degree ex. most charming<br /> - Demonstratives ex. this book, that door <br /> - Collective nouns ex. flock, class<br /> - The article the ex. The man in blue shorts<br /> - Personal pronouns – I, you, he, she, we, they, my, your, our <br />
  27. 27. Quantities of terms<br />PARTICULAR - it stands for an indefinite subject<br /> - Indefinite pronouns and adjectives<br /> ex. Some, several, many, few<br /> - Use of numbers ex. Seven tickets<br /> - Use of article “a” and “an”<br /> - General propositions: which are true most of the time but not all the time<br /> ex. Filipinos are hospitable<br />
  28. 28. Quantities of terms<br />3. UNIVERSAL – it stands for every subject signified<br /> - Universal expressions ex. All, every, each, whatever, whoever, whichever, without exception, everything<br /> - Universal ideas <br /> Ex. Men are mortal<br /> - The use of articles “the”, “a”, “an” if the idea is universal <br /> Ex. The snake is a dangerous creature.<br />
  29. 29. Seatwork #4<br />Underline each simple subject and classify its quantity: S for singular, P for particular, and U for universal<br />I am a violinist’s daughter.<br />All the children are musicians.<br />Six of them are a string ensemble.<br />A brother is a trombone player.<br />Some bands are their competitors during the town fiesta.<br />A square is a geometric figure with four equal sides. <br />Two parallel lines will not meet.<br />You should practice what you preach.<br />That girl beside me is wearing a red dress.<br />The weather is warm.<br />
  30. 30. Kinds of terms<br />UNIVOCAL – if they mean exactly the same thing in the last two occurrences<br /> Ex. Man is rational.<br /> Get that man!<br />EQUIVOCAL – if they have different meanings in at least two occurrences<br /> Ex. Man the lifeboat!<br /> The son of man<br />
  31. 31. Kinds of terms<br />3. ANALOGOUS – if they have partly the same and partly different meanings in at least two occurrences<br /> KINDS:<br /> 1. Intrinsic analogy: used in technical terms and as definitions<br /> 2. Extrinsic analogy: used as a metaphor<br /> Ex. The heart of the forest<br />
  32. 32. Kinds of terms<br />KINDS:<br /> 3. Analogy of Proportionality: when the terms use are similar <br /> Ex. The stepmother is cruel.<br /> The sea is cruel. <br /> 4.Analogy of Attribution: attribute the term to its denotation<br /> Ex. I am drinking Coke.<br />
  33. 33. Seatwork #5<br />Classify the underlined terms- write U for Univocal, E for Equivocal, IA for Intrinsic Analogy, EA for Extrinsic analogy, AP for for Analogy of Proportionality, AA for Analogy of Attribution.<br />I am reading Rizal.<br />Gold is a precious metal. Lydia de Vega received a gold for 100m. Dash.<br />Politicians speaks of leveling the Smokey Mountain. Geneva Cruz is a member of the Smokey Mountain. <br />Gonzaga is a tenor. Cabahug is a tenor.<br />I am using Colgate.<br />
  34. 34. Seatwork #5<br />Classify the underlined terms- write U for Univocal, E for Equivocal, IA for Intrinsic Analogy, EA for Extrinsic analogy, AP for Analogy of Proportionality, AA for Analogy of Attribution.<br />6. Father Sales and my father are friends.<br />7. The smiling sun is so brilliant.<br />8. The mouth of the river is clean.<br />9. We pass by Bridal’s Veil along Kennon Road<br />10. Hitler is a man.<br /> Marcos is a man.<br />
  35. 35. SUPPOSITION OF TERMS<br />It is functional – the way it is meant in the proposition<br />Examples:<br />A square is a rectangle with four equal sides.<br />Square has six letters<br />Square is the subject the sentence<br />A black-rimmed square clock is classy in my living room.<br />
  36. 36. KINDS OF SUPPOSITION<br />MATERIAL SUPPOSITION: is that which uses a word for itself alone, for its spoken or written sign, not for its real meaning<br />Examples: #2 and 3<br />FORMAL SUPPOSITION: is that which uses a word for its real meaning<br />Example: #1<br />
  37. 37. Other kinds <br />A] LOGICAL SUPPOSITION: is that which uses a word for its second intention; that is the way the mind thinks it to be<br />Example: #4<br />B] REAL SUPPOSITION: is that which uses a word in its first intention<br />Example: #1<br />
  38. 38. uNDER real supposition:<br />1] Absolute Supposition: is that which uses a word for essence, but without excluding existing reality<br />Example: Proposition #1<br /> Personal Supposition: is that which uses a word for the subject containing the essence signified by the word<br />Example: Proposition #4<br />
  39. 39. Essential Supposition: is that which uses a word for qualities necessary to the subject<br />Example: #1<br /> Accidental Supposition: is that which uses a word for qualities not actually necessary to the subject<br />Example: #4 <br />
  40. 40. Seatwork#6<br />Give the specific kind of supposition illustrated by<br />the words “carabao” and “pag-asa” in each<br />proposition below.<br />“Tamarao” belongs to the endangered species.<br />“Tamarao” is a word with three syllables.<br />“Pag-asa” is the name of the eaglet.<br />“Pag-asa” is the subject of the sentence.<br />“Pag-asa” means hope in English.<br />“Pag-asa” is now the adopted child of bird lovers.<br />
  41. 41. Other types<br /><ul><li>IMAGINARY SUPPOSITION: exists as a product of imagination</li></ul>Ex. Fictional character<br /><ul><li>METAPHORICAL SUPPOSITION: term is used as a figure of speech</li></ul>Ex. The smiling sun<br /><ul><li>SYMBOLIC SUPPOSITION: signifies a group of men </li></ul>Ex. L.A. Lakers<br />
  42. 42. The proposition<br /><ul><li>A special type of sentence
  43. 43. An enunciation of truth or falsity
  44. 44. Verbal expression of mental judgment</li></li></ul><li>STRUCTURAL ELEMENT<br /> S – C – P<br />[subject]- [copula]- [predicate]<br /><ul><li>Subject stands for the thing signified, the one spoken of
  45. 45. Predicate stands for what is affirmed or denied of the subject
  46. 46. copula- links the subject and the predicate
  47. 47. * acceptable only is the present tense is or is not</li></li></ul><li>example<br />All boys (are) future men.<br />Quantifier subject[S] copula[C] predicate[P]<br />
  48. 48. Logical symbol[Four standard propositions]<br />
  49. 49. examples<br />A - Every monkey is an animal.<br />E - No monkey is a human.<br />I - Some monkeys are brown.<br />O - Some monkeys are not brown.<br />
  50. 50. Logical diagram<br />A PROPOSITION<br />PREDICATE<br />SUBJECT<br />
  51. 51. E PROPOSITION<br />SUBJECT<br />PREDICATE<br />
  52. 52. I PROPOSITION<br />SUBJECT<br />PREDICATE<br />
  53. 53. O PROPOSITION<br />SUBJECT<br />PREDICATE<br />
  54. 54. LOGICAL FORM<br />WAYS OF REWRITING PROPOSITION TO ITS LOGICAL FORM<br />Change the verb to its present tense progressive.<br />Change the verb to a noun.<br />Change verb to a relative clause.<br />Change verb to a noun clause.<br />
  55. 55. example<br />ALL CROCODILES CANNOT FLY.<br />1.NO CROCODILES ARE FLYING.<br />2.NO CROCODILES ARE FLYERS.<br />3.NO CROCODILES ARE REPTILES THAT CAN FLY.<br />4.NO CROCODILES ARE FLYING REPTILES.<br />
  56. 56. SQUARE OF OPPOSITION<br />A<br />E<br />CONTRARY<br />S<br />U<br />B<br />A<br />L<br />T<br />E<br />R<br />N<br />S<br />U<br />B<br />A<br />L<br />T<br />E<br />R<br />N<br />CONTRADICTORIES<br />CONTRADICTORIES<br />SUBCONTRARY<br /> I<br />O<br />
  57. 57. CONTRADICTORIES<br /><ul><li>2 pairs: </li></ul>1] A – O: Every S is P, therefore, some S is not P.<br /> O – A: Some S is not P, therefore, every S is P.<br />2]E – I: No S is P, therefore, some S is P.<br /> I– E: Some S is P, therefore, no S is P.<br />
  58. 58. Examples:<br />A - All men are rational, therefore <br />O - some men are not rational.<br />I – Some students are girls, therefore <br />E – No students are girls. <br />
  59. 59. Rules:<br />1. If one is true, the other is false.<br />2. If one is false, the other is true.<br />A- All men are rational is true [ T ], therefore <br />O - some men are not rational. False or F<br />
  60. 60. contrary<br /><ul><li>1 pair:</li></ul>A – E: Every S is P, therefore, no S is P.<br /> or<br />E – A: No S is P, therefore, every S is P.<br />Example:<br />E- No students are girls, therefore, <br />A - every students are girls.<br />
  61. 61. Rules:<br />If one is true, the other is false.<br />If one is false, the other is doubtful.<br />Example:<br />E- No students are girls is false [ F ], therefore, <br />A - every students are girls is doubtful [ ? ]<br />
  62. 62. subcontrary<br /><ul><li>1 pair</li></ul>I – O: Some S is P, therefore some S is not P.<br /> or<br />O – I: Some S is not P, therefore some S is P.<br />EXAMPLE:<br />I - Some students are girls, therefore <br />O - some students are not girls.<br />
  63. 63. Rules:<br />If one is true, the other is doubtful.<br />If one is false, the other is true.<br />EXAMPLE:<br />I - Some students are girls is true [ T ], therefore <br />O - some students are not girls is doubtful [ ? ].<br />
  64. 64. subalterns<br /><ul><li>2 pairs</li></ul>1. A – I: Every S is P, therefore some S is P.<br /> I – A: Some S is P, therefore every S is P.<br />2. E – O: No S is P, therefore some S is not P.<br /> O – E: Some S is not P, therefore no S is P.<br />
  65. 65. example<br />A- All triangles are planes with three sides, therefore<br />I- Some triangles are planes with three sides.<br />
  66. 66. Rules:<br />1. If the universal is true, the particular is true; if the universal is false, the particular is doubtful<br />A- All triangles are planes with three sides is true [ T ], therefore<br />I- Some triangles are planes with three sides true [ T ].<br />
  67. 67. If the particular is true, the universal is<br />doubtful; but if the particular is false, the<br />universal is false.<br />I- Some triangles are planes with three<br />sides is true [ T ]<br />therefore<br />A- All triangles are planes with three sides is<br />Doubtful [?]<br />

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