Here.  It's an abbreviated version of the argument from his well-known paper "The Impossibility of Moral Responsibility," Philosophical Studies (1994).  There's a reasonably interesting discussion by philosophers here.  The comments at the Times site are, as usual, mostly hopeless, though my experience is that the Dunning-Kruger effect rules when it comes to who chooses to comment anonymously on web sites, so there is reason to hope that intelligent items like Galen's are more constructively received by the silent part of the public.