A radical historicist, he authored many books critical of the central assumptions of Western philosophy, and elaborated a robust form of relativism.

Margolis served in World War II as a paratrooper and was wounded during the Battle of the Bulge, where he lost his only brother, a twin.

Margolis taught at numerous universities in the United States and Canada and was invited to lecture throughout Europe, in Japan, New Zealand, and South Africa.

[5] As set out in Historied Thought, Constructed World (California, 1995), Margolis holds that philosophy is concerned principally with three things: He sees the history of philosophy concerning these three questions of reality, knowledge and ethics as a gradual movement away from the idea that any of these three realms is changeless and towards an increasing acceptance of real change infecting all three spheres.

Margolis defends the Protagorean dictum that "man is the measure of all things", arguing that all changeless first principles must give way to consensual, though not criterial, truth claims.

In Historied Thought, Constructed World (California, 1995), he argues that philosophy uncritically adopts the Platonic-Aristotelian view that "necessarily, reality is invariantly structured and, when known, discernibly known to be such".

For instance, Margolis argues that Aristotle's discussion of the principle of non-contradiction presupposes the changelessness of individual things rather than providing any proof of the alleged law.

Constative discourse – the making of statements of fact — for instance need only rely on identification, and reidentification, of items for it to prove effective in use.

Therefore, historical memory and consensus, together with a narratizing ability, are all that are necessary to ensure the stability of what we make reference to, there need be nothing essential at all in things themselves, for our constative discourse to be able to flourish and even thrive.

Margolis inveighs against postmodernists of Rorty's stamp, claiming that they risk disabling constative discourse in their objectivist fears of privilege.

Margolis acknowledges that the historized "nature" of the human—and therefore of truth, of judgment, of reality, and the rest - is not his own discovery, but criticizes most previous versions of historicism as falling victim to some theological or teleological yearning, as in Hegel's Geist, Marx's utopianism, or Heidegger's history of being.

Margolis argues that the cultural world is a semantically and semiotically dense domain, filled with self-interpreting texts, acts and artifacts.

Margolis has extensively criticized what he sees as scientism in philosophy, singling out thinkers such as Noam Chomsky, Paul Churchland, Jerry Fodor, and Daniel Dennett as modern-day defenders of invariance.