He is best known for proposing a theory of natural selection.

Second, it proposed a theory to explain how evolution works.

He was the first medieval physician to propose an original theory about blood and its role in the human system.

Others, such as Campbell, propose theories about hero stories in general.

I now wish to propose a theory about the performance of medieval and Renaissance music.

I would like to propose a theory now that, though strange, fits all the facts as we know them.

Later in life he proposed scientific theories of sweeping scope.

So maybe rather than propose new theories, we should spend our money gathering better information.

In 2010, he proposed a theory of light which contradicts relativity.

Much of the social contract philosophical traditional proposed a voluntary theory for state formation.