I believe, but cannot prove, that the human mind/brain is nothing more than a biological/chemical computer and that true AI is possible.
In other words, I do not believe in a spirit/soul that makes human intelligence unique. The reason we have not yet been able to reproduce it, is that it is a very complex system, that took bilions of years of evolution to develop.
However, some day, we will be able to. (Lets just hope that the AI's will not discover what useless and inefficient creatures humans are.

)