Once we have identified the property that A and B are supposed to
have in common--the property we're labeling S--we can put an
argument by analogy into a standard format. This format includes
an inductive step and a deductive step, and it allows us to
evaluate the argument by using what we have already learned about
induction and deduction.
To see how this works, let's continue with the analogy between
tennis and reasoning.
The common property here is that both are skills, and the
relevance of this property is that skills must be learned by
Tennis is a particular instance in which a skill requires
practice, and it serves as inductive evidence for a
generalization about all skills; this generalization is then
applied deductively to the case of reasoning.
The first step in the argument is the inductive one, supporting
the generalization that all skills require practice. This
generalization serves as a premise in the second step, which is
deductive, a categorical syllogism.
That premise expresses the link between skills and practice, and
without this premise, we have no basis for the conclusion.
The other premise says that reasoning is a skill--it states the
property that makes reasoning similar to tennis.
Two items being compared:
Logic and tennis
The respect in which they are similar:
They are both skills
The consequence of the similarity:
Being learned by practice
Tennis is a skill and tennis is learned by practice.
Therefore, all skills are learned by practice.
1.   All skills are learned by practice.
2. Logic is a skill.
3. Therefore, logic is learned by practice.