The Language of Argument

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8

Arguments To and From Generalizations

This chapter begins our investigation of inductive arguments by distinguishing the

inductive standard of strength from the deductive standard of validity. Inductive

arguments are defined as arguments that are intended to be strong rather than valid.

Two common examples of inductive arguments are discussed next. In statistical

generalizations, a claim is made about a population on the basis of features of a

sample of that population. In statistical applications, a claim is made about

members of a population on the basis of features of the population. Statistical gen-

eralizations take us up from samples to general claims, and statistical applications

then take us back down to individual cases.

Induction versus Deduction

The distinction between deductive arguments and inductive arguments can

be drawn in a variety of ways, but the fundamental difference concerns the

relationship that is claimed to hold between the premises and the conclusion

for each type of argument. An argument is deductive insofar as it is intended

or claimed to be valid. As we know from Chapter 5, an argument is valid if

and only if it is impossible for the conclusion to be false when its premises

are true. The following is a valid deductive argument:

All ravens are black.

[ If there is a raven on top of Pikes Peak, then it is black.

Because the premise lays down a universal principle governing all ravens, if it’s

true, then it must be true of all ravens (if any) on top of Pikes Peak. This same

relationship does not hold for invalid arguments. Nonetheless, arguments that

are not valid can still be deductive if they are intended or claimed to be valid.

In contrast, inductive arguments are not intended to be valid, so they

should not be criticized for being invalid. The following is an example of an

inductive argument:

All ravens that we have observed so far are black.

[ All ravens are black.

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