Leaving aside emotional appeals, persuasion is possible only because all human beings are born with a capacity for logical thought. It is sometimes we all have in common. The most rigorous form of logic, and hence the most persuasive, is the syllogism. If you have never studied logic, you may be surprised to learn—like the man who was astounded to discover that he had been speaking prose all his life—that you have been using syllogistic reasoning all along. Argument naturally falls into this mode, whether or not you set out to make it do so. But the clearer the syllogistic progression, the better.
Legal arguments can be expressed syllogistically in two ways. Some are positive syllogisms:
Major premise: All S is P.
Minor premise: This case is S.
Conclusion: This case is P.
Others are negative:
Major premise: Only S is P.
Minor premise: This case is S.
Conclusion: This case is not P.
If the major premise (the controlling rule) and the minor premise (the facts invoking that rule) are true (you must establish that they’re true), the conclusion follows inevitably.
Legal argument generally has three sources of major premises: a text (constitution, statue, regulation, ordinance, or contract), precedent (caselaw, etc.), and policy (i.e., consequences of the decision). Often the major premise is self-evident and acknowledged by both sides.
The minor premise, meanwhile, is derived from the facts of the case. There is much to be said for the proposition that “legal reasoning revolves mainly around the establishment of the minor premise.”
So if you’re arguing from precedent, your argument might go:
Major premise: Our cases establish establish that a prisoner has a claim for
harm caused by the state’s deliberate indifference to serious medical needs.
Minor premise: Guards at the Andersen Unit ignored the plaintiff’s complaints of acute abdominal pain for 48 hours, whereupon is appendix burst.
Conclusion: The plaintiff prisoner has a claim.
Or if you’re arguing text:
Major premise: Under the Indian Commerce Clause of the U.S. Constitution, states cannot tax Indian tribes for activities on reservations without the express authorization of Congress.
Minor premise: Without congressional authorization, South Dakota has has imposed its motor-fuel tax on tribes that sell fuel on reservations.
Conclusion: South Dakota’s tax is unconstitutional.
Or if you’re arguing policy:
Major premise: Only an interpretation that benefits the handicapped serves the policy objectives of the statute.
Minor premise: The defendant’s interpretation of the statute requires each wheel-chair bound employee to buy additional at cost of $1,800.
Conclusion: The defendant’s interpretation does not serve the policy objectives of the statute.
Figuring out the contents of a legal syllogism is a matter of finding a rule that works together with the facts of the case –really, a rule that is invoked by those facts. Typically, adversaries will be angling for different rules by emphasizing different facts. The victor will be the one who convinces decision-makers that his or her syllogism is closer to the case’s center of gravity. What is this legal problem mostly about? Your task as an advocate is to answer that question convincingly.