Complex sentence: He was a professor at Yale University from 1939 to 1946, but was denied tenure because of defense of emotivism, and then at the University of Michigan from 1946 to 1977.
Split into simpler sentences: He was a professor at Yale University from 1939 to 1946, but was denied tenure because of his defense of emotivism. He then taught at the University of Michigan from 1946 to 1977.