If one is satisfied with things, one doesn't complain about the downsides that exist, either.

Norm and Action 1963 (1958-60 Gifford Lectures St. 1980.

The first is analytic philosophy and philosophical logic in the Anglo-American vein. His best known article from this period is entitled The Myth of Progress and it questions whether our apparent material and technological progress can really be considered "progress". During the last twenty years of his life under the influence of Oswald Spengler Jürgen Habermas and the Frankfurt school's reflections about modern Rationality he wrote prolifically.