Stephen Toulmin, an influential philosopher who conducted wide-ranging inquiries into ethics, science and moral reasoning and developed a new approach to analyzing arguments known as the Toulmin model of argumentation, died on Dec. 4 in Los Angeles. He was 87.

The cause was heart failure, said his son Greg.

Mr. Toulmin, a disciple of Ludwig Wittgenstein, earned his undergraduate degree in mathematics and physics, and throughout his long philosophical career showed a marked inclination to ground his ideas in real-world situations.

In the introduction to a 1986 edition of his first book, “An Examination of the Place of Reason in Ethics” (1950), he wrote that “having been trained as a natural scientist, I had always hoped to relate philosophical issues to practical experience, and could never wholly side with Hume the philosopher against Hume the backgammon player.” His bent, he wrote, was toward “practical moral reasoning.”

Although he wrote on disparate topics like the history of science, international relations, medical ethics and Wittgenstein’s Vienna, he was best known for “The Uses of Argument,” published in 1958. In it, he criticized formal logic as an overly abstract, inadequate representation of how human beings actually argue. He also challenged its claims to universality, as well as its faith in absolute truth and moral certainty.