We humans are really fascinating machines, continuously fed with a huge stream of data which we learn to filter and analyze. It takes time to accumulate the data and refine our pattern matching until we seem to be intelligent. It's hard to draw a line when this happens.
Maybe everything happens so fast and seamlessly that we consider it to be something magic and simply call it intelligence? Or maybe there really is something in there, reading in-between the lines, a soul?
We all know that each of us is looking outside from somewhere within a brain and you are able to influence your actions. But, is it some kind of feedback loop which can be reproduced mechanically or something supernatural?
As long as we don't know this, every attempt to recreate general intelligence may be futile.
My own thinking on this has been very much influenced by an early AI researcher-turned-philosopher and HCI practitioner, Terry Winograd. His book Understanding Computers and Cognition has some solid arguments for seeing cognition as a trait evolved as a form of "structural coupling" between a living organism and its environment. Highly recommended for anyone looking for an alternate perspective on AI from someone who was doing it way, way before it was cool.