Benjamin Lee Whorf (; April 24, 1897 – July 26, 1941) was an American linguist and fire prevention engineer. Whorf is widely known as an advocate for the idea that differences between the structures of different languages shape how their speakers perceive and conceptualize the world. This principle has frequently been called the "Sapir–Whorf hypothesis", after him and his mentor Edward Sapir, but Whorf called it the principle of linguistic relativity, because he saw the idea as having implications similar to Einstein's principle of physical relativity. The idea, however, follows from post-Hegelian 19th century philosophy, especially from Wilhelm von Humboldt; and from Wilhelm Wundt's Völkerpsychologie.