Rhetorician and ethicist Stephen E. Toulmin has died.  While I haven’t been able to fit his full system into my freshman writing courses, I did create a brief handout on the Toulmin method.

Arguing against the absolute truth advocated in Plato’s idealized
formal logic, Toulmin said that truth can be relative. Historical and
cultural contexts, he said, must be taken into consideration.

He concluded that absolutism fails to consider the field-dependent
aspects of argument. Advocating a universal truth, absolutists believe
that a standard set of moral principles — regardless of context — can
solve all moral dilemmas. But Toulmin purported that many of these
standard principles cannot be applied to day-to-day life in the real
world.–USC News