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Roy Wood Sellars

American · North America · 1880 to 1973

Canadian-born American philosopher who argued for a naturalism rooted in evolution. He helped write the first Humanist Manifesto in 1933.

What it is

Roy Wood Sellars (1880 to 1973) was a Canadian-born American philosopher who argued that mind and life are products of an evolving, material world. He is also remembered as one of the authors of the first Humanist Manifesto of 1933.

He was born in Seaforth, Ontario, studied at the University of Michigan and spent most of his career teaching there. He was the father of the philosopher Wilfrid Sellars. He wrote on knowledge, on the nature of reality, on ethics and on politics.

The main ideas

  • Critical realism. He held that when we perceive, we perceive real things outside us. At the same time he took seriously that perception is shaped by the perceiver as well as by the things perceived, and he tried to do justice to both.
  • Evolutionary naturalism. He pictured the world as a material world that evolves through levels, with life and mind arising from it. Mind is the highest of these levels, and it belongs to nature.
  • Evolution as the base. He made evolution the base of his account of the world and of mind, and he called the result evolutionary naturalism.
  • Religious humanism. His own position was religious humanism: a religion brought into line with scientific knowledge.
  • Socialism. He supported socialism, which he understood as a democratic way of organising the economy that would give as much justice and liberty as can be had at any time.

What it looks like in practice

Imagine someone who looks at a tree and wonders whether anything is really there, or only a picture in their head. Sellars would say that the tree is there, and that the picture is shaped both by the tree and by the living body that sees it. Asked how a mind could belong to a world of matter, he would answer that mind is the highest level of an evolving material world. This is an illustration of his line of thought, not a passage from his books.

Books and moments

  • Critical Realism (1916) and The Next Step in Democracy (1916) were two of his early books, one on knowledge and one on politics.
  • Evolutionary Naturalism (1922) is the book in which he set out his view of evolution and the levels of nature.
  • Studies abroad. He studied for a time at the University of Paris, where he spoke with the philosopher Henri Bergson, and at Heidelberg with Hans Driesch and Wilhelm Windelband.
  • The Humanist Manifesto (1933) was a public statement of humanism. He is counted among its authors.

Questions and criticism

  • Is the middle path stable? He wanted to give weight both to the real object and to the perceiver. It is fair to ask whether that can be done without the view sliding toward one side or the other.
  • A new kind of religion? He treated humanism as a religion in its own right, built on science. Whether a view with no appeal to the supernatural can count as a religion is an open question.
  • Where does he belong? Later readers can ask whether he belongs with the naturalists, the realists or the humanists.

Close neighbours

His son Wilfrid Sellars has a page on this site. The school of secular humanism is the one most closely tied to his work on the Manifesto, and the page on Henri Bergson shows the thinker he spoke with in Paris.

Written by epchē in our own words, and checked against independent sources on 29 October 2026. The sources are listed below.

Philosophies they belong to or are close to

Who they connect to

Influenced

  • Wilfrid Sellars · His father, Roy Wood Sellars, was a philosopher of naturalism, and shaped his early thought.

Other American thinkers

Sources we used

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