Reading 1

• The actual strength of the link between premises and conclusion may allow one to determine whether an argument is inductive or deductive
• A geometrical proof is an example of an inductive argument
• Most arguments based on statistical reasoning are deductive
• If the conclusion of an argument follows merely from the definition of a word used in a premise, the argument is deductive
• An argument that draws a conclusion about a thing based on that thing's similarity to something else is a deductive argument
• An argument that draws a conclusion that something is true because someone has said that it is, is a deductive argument
• An argument that presents two alternatives and eliminates one, leaving the other as the conclusion, is an inductive argument
• An argument that proceeds from knowledge of a cause to knowledge of an effect is an inductive argument
• If an argument contains the phrase "it definitely follows that," then we know for certain that the argument is deductive
• An argument that predicts what will happen in the future, based on what has happened in the past, is an inductive argument
• Inductive arguments always proceed from the particular to the general
• Deductive arguments always proceed from the general to the particular
• If the conclusion of an argument should turn out to be false, in violation of our expectations, this occurrence would cause us to react with surprise
• Procedure for testing the strength of inductive arguments


  1. Assume the premises are true

  2. Determine whether, based on that assumption, the conclusion is probably true
• The determination of whether the conclusion is probably true is accomplished by linking up the premises with regularities that exist in our experiential background
• Types of regularities used to determine probability of conclusion

  • Causal patterns
  • Signs
  • Representativeness of sample
• All of these regularities are instances of the uniformity of nature
• If the conclusion of a deductive argument is necessarily true independently of the premises, the argument is still considered valid. But if the conclusion of an inductive argument is probably true independently of the premises, the argument is weak
• Combinations of truth/falsity of premises and conclusions in inductive arguments


  • True premise, probably true conclusion
  • True premise, probably false conclusion
  • False premise, probably true conclusion
  • False premise, probably false conclusion
• The only arrangement of truth and falsity that establishes an inductive argument as strong is true premises and probably false conclusion
• For an inductive argument to be strong, the conclusion must be more probable than improbable given that the premises are true
• Cogent argument

  An inductive argument that is strong and has all true premises that meet the total evidence requirement
• If any of the conditions for a cogent argument are missing, the argument is uncogent
• It is not always possible to determine the cogency of an inductive argument, just as it is not always possible to determine the soundness of a deductive argument