I think there is a further reason for wondering about whether one could construct an intelligent machine. One of the reasons which has traditionally been given for the difference between human persons and other animals is our capacity to reason. Man, according to Aristotle, is the rational animal . We are special because we have the ability to behave intelligently - even if we aren't often seen exercising that ability.
Intelligence is thus precious in the world.
The existence of an intelligent machine would doubtless teach us much about ourselves. Turing proposes a test of intelligence, which we discussed in some detail. After formulating what has since come to be known as the Turing Test, Turing proceeds to consider a number of arguments which conclude that no machine could be intelligent. Each argument is shown to be unsound, but, of course, Turing does not make the mistake of concluding on that basis that machines can , in principle, be intelligent. Turing does give us some reasons for thinking that an intelligent machine might someday be constructed.