Sarah B. Lawsky (UC-Irvine) presents How Models Work at Toronto today as part of its James Hausman Tax Law and Policy Workshop Series:

Unlike many social and physical sciences, including economics, biology, and physics, legal scholarship includes little or no discussion of what models mean, how they are connected to the real world of law and policy, or how models should and should not be used by legal scholars and policymakers. This void exists notwithstanding legal scholarship’s increasing reliance on explicit modeling, including, for example, work in law and economics. This article uses the example of economic modeling in tax scholarship to investigate how legal scholarship uses models, and how models in legal scholarship work.

The article lays out a path between two extremes. At one extreme is scholarship that employs models without either reflection or self-consciousness to make real-world recommendations; on the other, scholarship that rejects models because their assumptions are too far from reality. I argue that neither approach is correct. Models are useful and important for legal scholarship, but not in the way that both critics and proponents seem to believe.

Drawing from literature in the philosophy of science, the article argues that we reason from models the same way that we reason from common law cases: through a mix of deductive and inductive logic, through leaps, creativity, and intuition. Models cannot provide certainty about what the law should be; rather, economic models are one kind of voice in an ongoing, necessarily inconclusive conversation. The article then uses this deeper understanding of models and modeling to propose ways that legal scholarship can and should use models.