What it is to be a human being and what it is to be a machine

When you consider the difference between a human being and a machine, you start with some idea about what it is to be a human being and what it is to be a machine.

 Some people now celebrate the technological advances that can make it hard to tell the difference; others view that difficulty with anxiety. 

They are concerned when machines do what we want to do; and they have species-self-doubt when machines do things that once defined what it was to be uniquely human. The worst worry is that the machines will refuse our orders, that they may acquire a will of their own, and want free agency.