Thinking and Deciding

EXTENSIONS OF LOGIC 95
Table 4.1: Some types of warrants
Warrant type Definition of type Example
Meta Based on the process of problem
solving
Governmental Based on general knowledge
of the way governments function
Logical Based on general logical reasoning
or common sense
Psychological Deriving from general rules of
human behavior
Analogical Based on reasoning from what
is known about a different system
to conclusions about the
target system
Solving a problem requires
defining the constraints of the
problem.
Ministries of governments solve
central problems slowly.
If an approach is unsuccessful, it
should be abandoned.
People work harder when they
are given incentives to work.
In Latin America, the peasants
find extralegal ways to obtain
money; this is probably true in
the USSR.
Source: Adapted from J. F. Voss, S. W. Tyler, and L. A. Yengo, “Individual Differences
in the Solving of Social Science Problems,” in R. F. Dillon and R. R. Schmeck
(Eds.), Individual Differences in Cognition (New York: Academic Press), Vol. 1, p.
213.
Datum
✲ Qualifier,Claim
Warrant Rebuttal
Backing
Warrants are of different types. Some warrants are specific to certain topics,
such as law, science, mathematics, human behavior, or plumbing. In law, warrants
can consist of laws and precedents set by previous cases. In science, they can be
previous findings, analogies, and accepted laws.
Voss, Tyler, and Yengo (1983) applied Toulmin’s scheme to actual reasoning in
social sciences. They asked experts on the Soviet Union, and others, to discuss the
problem of how to improve Soviet agriculture. Some of the kinds of warrants they
discovered are listed in Table 10.1. For example, the psychological warrant about
incentives might be used to justify a claim that certain Soviet workers would work
harder with incentives, based on the datum that they are not now given incentives.
That datum, in turn, might be a claim that was reached in a different argument. Of
course, qualifiers such as “probably” or “presumably” would have to be inserted.