I think you may have a fundamental misunderstanding of life, the universe, and everything. Suppose we can simulate interactions between atoms nearly perfectly on a computer... then it's just a matter of making an atom-for-atom digital replication of the brain (understanding of course that this is all easier said than done, but all possible). Once that is achieved, we optimize and make it even better by thinking faster and more accurately than we ever could. What are you missing from this? Or is hacker news really starting to be trolled... because I might just cry.