A Heuristic for Argument Analysis

— Consider 2 players, Q and A, in a question-answer game:

• Q asks a question (step 1 below)
• A gives an alleged answer (step 2 below)
• Q must verify A's alleged answer (steps 3–4 below)

1. Q asks "C?".

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2. A answers "C, because P₁ & P₂".
   • I.e., A gives an argument for conclusion C with premises (reasons) P₁ & P₂.

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3. Q must analyze or verify A's argument:
   1. Do I [Q] believe (i.e., agree with) P₁?
      • Note that this is a recursive step:
        • Q could ask A: "P₁?"
        • And A could give an argument for conclusion P₁ with new premises P₃ & P₄, etc.

   2. Do I believe (i.e., agree with) P₂?
      • This is similarly recursive.

   3. Does C follow validly from P₁ & P₂?
      • More generally, does C follow rationally from P₁ & P₂
        (if not deductively validly, then perhaps inductively? abductively, etc.?)?

      • This is arguably not similarly recursive on pain of infinite regress,
        at least according to one interpretation of a famous philosophy article by Lewis Carroll
        (see "Carroll's paradox").

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4. Then Q must reason in one of the following ways:
   1. If I [Q] agree with P₁
      and if I agree with P₂
      and if C follows validly (or rationally) from P₁ & P₂
      then I logically must agree with C.

   2. But if I really don't agree with C,
      then I must reconsider my agreement with P₁
      or with P₂
      or with the logic of (P₁ & P₂) → C

   3. If I agree with P₁
      and if I agree with P₂
      but the argument is invalid,
      is there a missing premise P₃ that would validate the argument and that I would agree with?
      • If so, then I can accept C
        else I should not reject C
        but I do need a new argument for C

   4. If I disagree with P₁ or with P₂
      then this argument is not a reason for me to believe C;
      so I need a new argument for C.

(Figure courtesy of Tom Fadial.)