specifically writtent into the illustrations of the various forms of reasoning the
relationshipe between them will be apparent.
Deduction
Deduction works in the following way. There is a rule R that says: “A causes
B” (meaning that A always causes B). In this instance A has occurred.
Thefore, rule R asserts, B has also occurred. In other words, deduction is the
process of using the rule (R) to derive
the consequences (B) from
what is
known to have occurred (A).
In deductive reasoning when a premise says that “A causes B” it is assumed
that this is a rule. However, to emphasise the relationship between the various
forms of reasoning the syllogism can be set out with the rule, Rule R in the
example, written into the major premise:
Components
Relationships
Major Premise
Rule R says: “A causes B”.
Minor Premise
A occurs
Conclusion
Therefore B occurs
Figure 4.5 Form of Deduction
It is clear from this diagram what deduction does to Rule R. Deduction is the
way in which Rule R operates. It shows Rule R at work.
Induction
With induction, there are numerous observations made. Each observation
invovles A causing B. Induction reasons to the existence of the rRule R
proclaiming that A always causes B. In other words, induction involves
observing the operation of the rule then deriving its existence.
Where the rule whose existence is established by induction is Rule R, the
induction takes the following form:
Premise
In all observed instances A causes B.
Conclusion
There is a rule, Rule R, that says “A causes B”.
Figure 4.6 Form of Induction
This diagram makes clear the relationships between induction and Rule R.
Induction establishes the existence of Rule R and establishes the likelihood
that Rule R is correct without conclusively demonstrating that it is correct.
Abduction
With abduction, one observes the occurrence of B. Abduction searches for
explanation and finds that the most preferable explanation is that there is a rule,
Rule R, which says that A causes B. Thus
abduction works in reverse to
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