Today’s proposition

Devon Eriksen (via Nicholas):

Heinlein was one of the 20th century’s greatest authors, if not THE greatest, and he was also the 20th century’s greatest philosopher and it’s not even close.

Is this defensible? I’ve read an immense amount of science fiction but little Heinlein¹, and what Heinlein I have read didn’t particularly impress me. Are there depths to Starship Troopers and The Moon is a Harsh Mistress that are missing in what I have read?

1. Glory Road, Stranger in a Strange Land and a handful of short stories, all back when I was young and skinny.