Turing believed that by the end of the 20th century             it would be possible to program a digital computer  to play the imitation game.  Although modern computers still cannot pass the Turing test, it provides a basis for the verification and validation  of knowledge-based systems.
A program thought intelligent in some narrow area of expertise is evaluated by comparing its performance with the performance of a human expert.
To build an intelligent computer system, we have to capture, organise and use human expert knowledge in some narrow area of expertise.