The Possible is not Necessarily the Desirable
From the IEET Blog, a look at plausible outcomes in advancing computational power and biotechnology - such as being able to emulate a human brain in software. I have no doubt that this will happen within the next few decades, but is it desirable? A human mind running on software could last as a pattern for as long as civilization persists, but unless deliberately engineered for continuity it would not survive as an individual in the way we presently understand that term. For example: we are quite used to moving data from hard drive to hard drive, restoring from backups when data becomes corrupt, and constantly shifting the running of software from machine to machine. Cost-effective human emulations would likely undergo exactly these sorts of events under the hood. If you are concerned with personal continuity, as I am, this would be an existential nightmare - you would exist as a flickering series of different people, each one killed by the normal operation of computing systems, and then the next picks up where the prior left off. Yet it will be quite possible to engineer an artificial brain in software and hardware that has continuity in the same way as we do presently: a collection of nanomachines, each machine playing the role of a single neuron, for example. That strategy is probably not cost-effective in comparison to running everything in software, however - and most people won't care about the existential issues so long as everything looks good from the outside.