Check out "Godel, Escher, Bach" by Douglas Hofstadter, he tackles that question and argues from the point of view that hard ai is possible. Check out "Emperor's new mind" by roger penrose for a conflicting viewpoint. Both books will teach you much, much more than it's central thesis and is a tour through other important topics in science.

Also, you might find the brain science podcast ( http://brainsciencpodcast.wordpress.com ) interesting. She tackles some of these questions also, summarizes current research and interviews other people in the field.