"The brain" literally refers to the portion of the vertebrate central nervous system that constitutes the organ of thought and neural coordination. It includes all the higher nervous centers, which receive stimuli from the sense organs and interpret and correlate them to formulate the motor impulses.
Ray Kurzweil challenges our perceptions about the human brain. "Exponential growth is not restricted to hardware, but with accelerating gains in brain reverse engineering, also applies to software. Within a few decades, machine intelligence will surpass human intelligence, allowing nonbiological intelligence to combine the subtleties of human intelligence with the speed and knowledge sharing ability of machines. The results will include the merger of biological and nonbiological intelligence, downloading the brain and immortal software-based humans -- the next step in evolution."
Originally published in print June 18, 2002 in Are We Spiritual Machines? Ray Kurzweil vs. the Critics of Strong AI by the Discovery Institute. Published on KurzweilAI.net on June 18, 2002.
For further discussion about the brain: http://www.kurzweilai.net/meme/frame.html?main=/articles/art0500.html