Solo diving II. In the late 1940s, after the invention of the Aqua-lung by Cousteau and Gagnan, the first retail underwater breathing apparatus for sport was commercially marketed. As the sport expanded through the 1950s, several sporting organisations – notably the Young Men's Christian Association (YMCA) – began scuba training programmes for swimming enthusiasts, thus began the codification of what was believed to be proper practices for the expanding amateur sport of scuba diving. The buddy system was thought to be a useful corollary to the "never swim alone" edicts of the YMCA swimming and lifesaving programmes. Cousteau independently implemented a buddy
20th-century French philosophy linguistics in the 20th century. He is widely considered the 'father' of 20th-century linguistics. This current was further explored by Claude-Levi Strauss in ethnology. His work influenced important figures like Jacques Derrida and Jacques Lacan significantly. From 1963, a magazine was run in Paris, called Tel Quel, which also dabbled excessively in structuralist analysis of texts. Important figures in this endeavour were Phillip Sollers, the magazine's editor, Julia Kristeva and Roland Barthes. Jacques Lacan (1901–1981) was specifically interested in the philosophy of psychoanalysis. He could be said to be relevant to the more modern foundations of discursive psychology. Post-structuralism is,