Second, evolution only improves what it already has. Over generations, the build plans for the body and brain can be changed and improved, but they are modifications of previous plans. This means solutions aren’t necessary the best ones. As the joke goes, a tourist asks, ‘How do I get to London?’ and gets the reply ‘Well, I wouldn’t start from here.’ A desktop computer may be better suited for solving some problems the human brain faces, but evolution has committed to doing things with neurons, with whatever limitations that involves. Evolution can only improve what neurons can do; it can’t switch to silicon.