LISP is now the second oldest programming language in present widespread use (after FORTRAN)... Its core occupies some kind of local optimum in the space of programming languages given that static friction discourages purely notational changes. Recursive use of conditional expressions, representation of symbolic information externally by lists and internally by list structure, and representation of program in the same way will probably have a very long life.

John McCarthy (1979) "History of Lisp," as quoted in: Avron Barr, Edward Feigenbaum. The Handbook of artificial intelligence, Volume 2. Addison-Wesley, 1986. p. 5