We should have great respect for what seem like the most mundane of analogies, for when they are examined, they often can be seen to have sprung from… - Douglas Hofstadter

Historically, people have been naive about what qualities, if mechanized, would undeniably constitute intelligence. Is intelligence an ability to integrate functions symbolically? If so, then AI already exists, since symbolic integration routines outdo the best people in most cases.
If intelligence involves learning, creativity, emotional responses, a sense of beauty, a sense of self, then there is a long road ahead, and it may be that these will only be realized when we have totally duplicated a living brain.

No thought can be formed that isn’t informed by the past; or, more precisely, we think only thanks to analogies that link our present to our past.

Sometimes it seems as though each new step towards AI, rather than producing something which everyone agrees is real intelligence, merely reveals what real intelligence is not.