Legal reasoning and interpretation

See also the discussion of legal reasoning and interpretation in our Research Study on Text-driven Law.

Working definition

• Legal reasoning concerns the justification of the determination of legal effect in a specific case. The justification is provided in the form of a syllogism:

  1. The major: a legal norm that attributes specified legal effect if specified legal conditions are fulfilled
  2. The minor: a specified set of legally relevant facts that, supported by evidence, fulfil the relevant legal conditions
  3. The conclusion: the attribution of the specified legal effect
• The syllogism is not a method to find the legal effect but a way to test whether a legal norm does or does not apply. This test requires to choose the relevant legal norm, and both interpretation and legal reasoning.

• The syllogism requires interpretation of the legal norm in the light of the facts and interpretation of the facts in the light of the legal norm. The following types of interpretation are deemed valid:

  1. Ordinary meaning (grammatical or literal interpretation) based on the prevailing meaning of the norm’s written articulation
  2. Framers’ intent (the intent of the legislature) as inferred from official documents
  3. Systematic interpretation based on the role the relevant norm plays in the context of the relevant legal system (its place in the relevant statute, its relationship with other norms whether higher norms such as a Constitution or Treaty or precedent)
  4. Teleological interpretation based on the purpose of the relevant legal norm, taking framers’ intent, ordinary meaning and systematic interpretation into account

• The syllogism requires a decision about the extent to which a case is like or unlike other relevant cases. Such a decision requires one of two types of reasoning:

  1. By analogy, arguing that since one case is like another the same legal norms applies to both
  2. A contrario, arguing that since one case is different from another the same legal norm does not apply to both
• Legal reasoning is often defined as deontological reasoning (not about how things are but about how they should be) and understood as non-monotonic and defeasible logic. This means that whereas ‘if a then b’ is correct for now, additional information may render it incorrect.

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This section's contents

• Examples