magine a group of people coming uninvited to your home, measuring the length of your nose or assessing the exact shade of your hair, and then using these attributes to decide that you must be taken away and locked up alone in a tiny cell – without any visiting rights for the people you love. Imagine that after nearly a year of this unconscionable torture, a judge decrees that you be put to death. Now imagine (and since you're a human reader, this will place stronger demands on your powers of empathy) that you have no language or means of communication with your captors, no idea why your world has become a living hell, and no sense of the possibility that things might ever get better.

For 11 months now, a docile dog named Lennox — a Bulldog-Labrador cross — has suffered exactly this fate in Northern Ireland. When the Belfast City Council decided that Lennox was a possible "Pit Bull type", they took him away from his family, including a disabled 12-year-old girl for whom he was a companion, and locked him up – all because of an archaic, breed-specific legislation (BSL) that says Pit Bulls must be destroyed. BSL is based on the notion that certain dog breeds are insuppressibly dangerous, regardless of the environment they were raised in (in this case, a loving family and completely domesticated conditions). Speaking in human terms, this is dangerously close to the generalisations that have been offered as justifications for racism at various points in our history.

hat does all this have to do with a books column? Well, the more I read about the Lennox case, with its mix of incompetence, prejudice and inhumanity, the more I think about the writings of Peter Singer, Jeremy Bentham and other ethical philosophers. Their work touches on subjects that are of vital importance to human morality, including our responsibilities — as the planet's biggest-brained species — to those who are weaker than us. Singer, whose landmark book Animal Liberation was published in 1975, has made compelling arguments against "speciesism", which he believes will one day be just as unacceptable as racism and sexism are today. "Despite obvious differences between humans and nonhuman animals," he writes, "we share with them a capacity to suffer – and this means that they, like us, have interests." This is an expansion of ideas expressed by Bentham as long ago as the early 1800s. One of the first proponents of animal rights, Bentham had argued that the benchmark (or "insuperable line") for determining a creature's welfare is not "Can it reason?" but "Can it suffer?"

That was a radical argument for an age when most humans didn't have freedoms in the sense that we understand them today. During Bentham's lifetime, Mary Wollstonecraft's proto-feminist Vindication of the Rights of Women was satirised in a tract titled A Vindication of the Rights of Brutes, which mockingly wondered if Wollstonecraft's arguments might not be applied to dogs, cats and horses too! Needless to say, in the centuries since, the sphere of acceptance has widened to include women as well as humans of all races and colours. But it can widen further: as Singer points out, one should always be wary of talking about "the last remaining form of discrimination".

The dilution of religious certitudes and the publication of On the Origin of Species has helped us reassess our relationship with other life forms. In the post-Darwin world, no thinking person can crouch behind the idea that humans are "special" beings made in the image of God, and with complete dominion over "inferior" species. As Richard Dawkins points out in his essay "Gaps in the Mind", any comfortable assumptions about human superiority (and the consequent prioritising of our rights) would be blown out of the water if we had a chance to see all the countless intermediate creatures that link us with other species.

What we do have, to a greater degree than other animals, is the ability to reason and to take responsibility for our actions, and the senseless handling of the Lennox case should give any right-minded homo sapien pause for thought. I hope he's freed soon.