Let's look at some at current AI programs: (1) Robots, e.g. self drive cars. In the DARPA grand challenge, the superior car-driving software was not Lisp. Rather it was a procedural language such as C++ or Java. (2) Machine translation of natural language. Lisp is not used for this purpose by widely used production systems. (3) Game playing, e.g. chess programs. Lisp is not used for this purpose by widely-used, superior chess programs such as Fritz.<p>Lisp was invented and developed by US AI labs in the 1960's in order to rapidly prototype symbolic logic programs in which the native Lisp data structures fit the level of symbolic abstraction required - e.g. English words could be symbols in a list, logic formulas could be easily represented as lists of operators and operands.<p>But for production programs, the software engineering advantages of static typed languages and a wide variety of third-party libraries, means that Lisp is not even considered for large modern systems that perform AI tasks.