Introduction

Philosophy (“the love of wisdom”) is an attitude of critical and systematic thoughtfulness. The ideal of Western philosophy is, in a phrase, thinking for yourself.

Argument involves at least two components: logic and rhetoric. Logic concerns reasons that should hold for anyone, anywhere. Rhetoric involves personal appeals. There are two primary forms of logical argument: deductive and inductive.

Deductive arguments reason from one statement to another by means of accepted logical rules; anyone who accepts the premises is bound logically to accept the conclusion. A deductive argument is valid when it correctly conforms to the rules of deduction, where it is impossible for the premise(s) to be true and the conclusion false. A valid argument can still have a conclusion that is false, if the premises are not true. An argument is sound if the premises are true and the argument is valid. A fallacy is an invalid argument. In deduction, the conclusion never states more than the premises (the conclusion is already “contained in” the premises). A syllogism is a deductive argument with two premises and a conclusion, usually involving membership in groups, and using the terms “all”, “some”, and “none”.

Inductive arguments infer one statement from another, but it is possible for the conclusion to be false even if all of the premises are true. In an inductive argument, the conclusion always states more than premises. It is, therefore, a less certain form of argument. The tentative conclusion is a hypothesis, an educated guess on the basis of the evidence collected thus far. A counterexample is a piece of evidence that refutes the hypothesis.

An argument by analogy defends the similarity between some aspect of two things on the basis of their similarity in other respects. It may employ both deductive and inductive elements. Care must be taken to make sure that the two things compared are significantly similar and, most importantly, that the aspect that is argued about is significantly similar in both cases.

A necessary condition is one in which B can’t happen without A (A is a necessary condition for B). A sufficient condition is one in which A is enough to guarantee B (A is a sufficient condition for B). A necessary and sufficient condition is one in which A is necessary and sufficient for B when A is both required for B and enough to guarantee B. Challenging a philosophical definition does not require an actual counterexample; it is enough to imagine a mere logically possible counterexample.

Reductio ad absurdum is a form of “indirect” deductive argument. It consists of taking your opponent’s view and showing that is has intolerable or contradictory consequences.

The following are examples of fallacies:

  • Mere assertion. Stating your view is not an argument for it.
  • Begging the question uses the conclusion of an argument as one of its premises.
  • Vicious circle is, for example, arguing A because of B, and B because of C, and then C because of A.
  • Irrelevancies are anything but which gets to the point.
  • Ad hominem arguments are personal attacks instead of arguments against the position.
  • Unclear or shifting conclusions.
  • Changing meanings.
  • Distraction, or a red herring.
  • Pseudo-questions look like real questions but are ultimately unanswerable because they are based on some hidden piece of nonsense.
  • Dubious authority, or an appeal to authority (when it is the wrong authority).
  • Slippery slope.
  • Attacking a straw man.
  • Pity (and other emotional appeals).
  • Appeal to force. Physical might never makes philosophical right.
  • Inappropriate arguments.
Profiles
Integrated readings

—September 2020