I warned you this was going to get a bit Continental—but actually making acts define the agent rather than the other way about may not be as unpalatably radical as all that. He clearly likes Levinas’ drift, anyway, and perhaps even better Silvia Benso’s proposed ‘mash-up’ which combines Levinasian non-ethics with Heideggerian non-things (tempting but a little unfair to ask what kind of sense that presumably makes).

Actually the least appealing proposal reported by Gunkel, to me at least, is that of Anne Foerst, who would reduce personhood to a social construct which we assign or withhold. This seems dangerously close to suggesting that, say, concentration camp guards can actually withdraw real moral patienthood from their victims and hence escape blame (I’m sure that’s not what she actually means).

However, on the brink of all this heady radicalism Gunkel retreats to common sense. At the beginning of the book he suggested that Descartes could be seen as "the bad guy" in his reduction of animals to the status of machines and exclusion of both from the moral realm; but perhaps after all, he concludes, we are in the end obliged to imitate Descartes’ provisional approach to life, living according to the norms of our society while the philosophical issues resist final resolution. This gives the book a bit of a dying fall and cannot but seem a bit of a cop-out.

Overall, though, the book provides a galaxy of challenging thought to which I haven’t done anything like justice and Gunkel does a fine job of lucid and concise exposition. That said, I don’t find myself in sympathy with his outlook. For Gunkel and others in his tradition the ethical question is essentially political and under our control. Membership of the moral sphere is something that can be given or not given rather like the franchise. It’s not really a matter of empirical or scientific fact, which helps explain Gunkel’s willingness to use fictional examples and his relative lack of interest in what digital computers actually can and cannot do. While politics and social convention are certainly important aspects of the matter, I believe we are also talking about real, objective capacities which cannot be granted or held back by the fiat of society any more than the ability to see or speak. To put it in a way Gunkel might find more congenial: when ethnic minorities and women are granted equal moral status, it isn’t simply an arbitrary concession of power, the result of a social tug-of-war but the recognition of hard facts about the equality of human moral capacity.

Myself I should say that moral agency is very largely a matter of understanding what you are doing; an ability to allow foreseen contingencies to influence current action. This is something machines might well achieve: arguably the only reason they haven’t got it already is an understandable human reluctance to trust free-ranging computational decision-making given an observable tendency for programs to fail more disastrously and less gracefully than human minds.

Moral patienthood on the other hand is indeed partly a matter of matter of the ability to experience pain and other forms of suffering, and that is problematic for machines; but it’s also a matter of projects and wishes, and machines fall outside consideration here because they simply don’t have any. They literally don’t care, and hence they simply aren’t in the game.

That seems to leave me with machines that I should praise and blame but need not worry about harming. Should be good for a robot butler, anyway.

Peter Hankins is author of the Conscious Entities weblog.