Isn't the brain just a machine?

Isn't the brain just a machine itself? Where do we has human's draw the line between machine and living? This topic is obscurred with more questions than solutions. It seems theoretically possible that one day humans will be able to construct a robot that will function identically as human. That being said, if the brain can be reconstructed completely, what really is the difference? organic tissue? emotions and what we consider consciousness can be programmed into a computer. I dont see why we cannot create a virtual human one day, much like the bicentinal man with robin williams Laughing . That's my two cents on the subject.