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← What is an Argument?

This video introduces the concept of an ARGUMENT as the term is used in logic and argumentation.

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Showing Revision 3 created 01/18/2020 by Claude Almansi.

  1. SPEAKER 1: Since arguments
    are at the heart of logic
  2. and argumentation, it's natural
    to start with this question.
  3. The first thing to
    say about arguments
  4. is that as this term
    is used in logic,
  5. it isn't intended
    to imply anything
  6. like an emotional confrontation.
  7. Like when I say that an
    argument broke out at a bar,
  8. or I just had a huge
    argument with my parents
  9. about my grades or something.
  10. In logic, an argument
    is a technical term.
  11. It doesn't carry any
    connotation about conflict
  12. or confrontation.
  13. So here's our definition.
  14. It'll have the three parts.
  15. First part, an argument is a
    set of claims or statements.
  16. We'll have more to say about
    what a claim or statement is
  17. later, but for now,
    it's enough to say
  18. that a claim is the
    sort of thing that
  19. can be true or false.
  20. Next part, one of the
    claims is singled out
  21. for special attention.
  22. We call it a conclusion.
  23. The remaining claims
    are called premises.
  24. And finally, the premises are
    interpreted as offering reasons
  25. to believe or accept
    the conclusion.
  26. That's it.
  27. That's the definition
    of an argument.
  28. Now let's have a look at one.
  29. All musicians can read music.
  30. John is a musician.
  31. Therefore, John can read music.
  32. These are the premises,
    and this is the conclusion.
  33. Premises one and two are
    being offered as reason
  34. to accept the conclusion
    that John can read music.
  35. This may not be a particularly
    good argument, actually,
  36. since that first premise makes
    a pretty broad generalization
  37. about all musicians that isn't
    very plausible, I don't think.
  38. I'm sure there are a few
    great musicians out there that
  39. don't read sheet music, but
    it's an argument nonetheless.
  40. Now, notice how
    it's been written.
  41. The premises are each numbered
    and put on separate lines,
  42. and the conclusion is
    placed at the bottom
  43. and set off from the rest by a
    line and flagged with the word
  44. therefore.
  45. This is called putting an
    argument in standard form,
  46. and it could be useful when
    you're doing argument analysis.
  47. In ordinary language, we
    almost never are this formal,
  48. but when you're trying to
    analyze arguments, when you're
  49. investigating your
    logical properties,
  50. or considering whether the
    premises are true or not,
  51. putting an argument
    in standard form
  52. can make life a lot easier.
  53. And just to
    highlight this point,
  54. here's another way of
    saying the same thing.
  55. Can John read music?
  56. Of course.
  57. He's a musician, isn't he?
  58. These actually express
    the very same argument,
  59. but notice how much
    easier it is to see
  60. the structure of
    the argument when
  61. it's written in standard form.
  62. In the second version
    in yellow here, you
  63. have to infer the conclusion
    John can read music
  64. from the opening question
    and the of course part,
  65. and you have to fill
    in an assumed premise.
  66. What you're given is
    Jon is a musician,
  67. but the conclusion only follows.
  68. If you assume that all
    musicians, or most musicians,
  69. can read music,
    which is not given.
  70. It's just a
    background assumption.
  71. The argument only makes
    sense because you're
  72. filling in the background
    premise automatically,
  73. but you can imagine
    that this might become
  74. a problem for more
    complex arguments
  75. where you can't always be
    sure that everyone is filling
  76. in the same background premise.
  77. So the standard
    form can be helpful,
  78. and we're going to be using
    it a lot in this course.
  79. Here are the takeaway points
    to remember from this.
  80. First, an argument is
    just a set of claims
  81. that are offered as reasons
    to believe or accept
  82. another claim.
  83. Second, we saw that
    the same argument can
  84. be written in more than one
    way, and in general it's
  85. true that the same argument
    can be written or expressed
  86. in many different ways
    using different words,
  87. different sentences, and
    different sentence structure.
  88. Now, because of
    this, it is often
  89. helpful to put arguments
    in standard form
  90. where you can clearly identify
    which parts of the argument
  91. are functioning as
    the premises and which
  92. part is the conclusion.
  93. And you make all the premises
    and background assumptions
  94. explicit by writing
    them on separate lines.
  95. Being able to do
    this is actually
  96. an important skill in logic.