Animals are an object of concern, and, as we extend our control over the earth’s resources, ever more so.

The old way of distinguishing humans from other animals - in terms of the soul, God’s purpose, and the after-life - is no longer universally accepted, and the Darwinian theory of species has unsettled people’s moral perceptions. Is there any way of making the distinction between humans and other animals, therefore, that could recommend itself to modern, secular, sceptical people who believe nevertheless in the difference between right and wrong?