Components
Relationships
Major Premise
Rule R says: A causes B
Minor Premise
A occurs
Conclusion
Therefore B occurs
Figure 4.1 Form of Deduction
Operation of Deduction
In working with law the operation of deduction needs to be considered in four
circumstances:
(1)
Applying Law to Facts. This is clearly a process based on deduction.
This is linked to the fact that legal rules are generally conditional statements
which form the major premise of the syllogism.
(2)
Interpreting Law. Interpreting a legal rule appears to be based on a
syllogism when the law is interpreted by simple application of a precedent or
of the policy underlying the statute in which the legal rule appears. However,
the process is syllogistic only because the interpreter accepts the precedent or
policy as correct and binding.
(3)
Ascertaining Values. Deduction cannot prove the existence or authority
of values. Nevertheless, natural law scholars proclaimed that there was a
universal code of conduct for all humans that could be ascertained by pure
reason.
(4)
Ascertaining Causal Laws. Causal law are established as plausibly
correct by use of deduction with the process that is labelled the hypothetico-
deductive model.
(5)
Proving Facts. Deduction is used to prove facts when scientific analyis
is used. One fact is observed and scientific analysis enables additional facts to
be proved based on the observed fact.
Induction
Nature of Induction
Induction is a form of generalisation. If all crows that one sees are black one
might formulate the rule that all crows are in fact black. The reasoning is not
watertight but has some strength. Induction can be set out in the following
diagram:
Premise
In all observed instances A causes B.
Conclusion
There is a rule, Rule R which says: “A causes B”.
Figure 4.2 Form of Induction
Operation of Induction
In working with law the operation of induction needs to be considered in two
circumstances:
(1)
Ascertaining Values. Induction cannot be used for establishing the
existence or authority of values although, as noted above, natural law scholars
 |
 |
 |