In a recent silicon.com interview with Ray Kurzweil, the question of whether or not machines will ever have souls came up. The interviewer didn't define what was meant by soul, so Kurzweil gives his definition as part of the answer. He suggests that "soul" is a synonym for consciousness. So the question really is, will machines ever be conscious. He believes consciousness is an emergent property; "Brain science is instructive there as we look inside the brain, and we've now looked at it in exquisite detail, you don't see anything that can be identified as a soul - there's just a lot of neurons and they're complicated but there's no consciousness to be seen. Therefore it's an emerging property of a very complex system that can reflect on itself. And if you were to create a system that had similar properties, similar level of complexity it would therefore have the same emerging property." He also predicts that, over time, humans will have more and more machine parts until the distinction between robots and humans becomes "all mixed up". He goes on to answer questions about why AI researchers are using the human brain as a model for intelligence, whether there are jobs machine will not be able to do better than humans, and what the downsides to advanced technology is.