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What AI is:
Artificial Intelligence (AI) is the study of intelligent behaviour (in humans, animals, and machines) and the attempt to find ways in which such behaviour could be engineered in any type of artefact. It is one of the most difficult and arguably the most exciting enterprise ever undertaken by humanity. The difficulty of the enterprise may not be obvious at first, but it has been painfully learned.
Which thing has been painfully learned? Is it the the enterprise or the difficulty ?