The idea that all the entities in the world may be, for legal and moral purposes, divided into the two categories of ‘persons’ and ‘things’ comes down to us from the tradition of Roman law. In the law, a ‘person’ is essentially the subject of rights and obligations, while a thing may be owned as property. In ethics, a person is an object of respect, to be valued for her own sake, and never to be used as a mere means to an end, while a thing has only a derivative value, and may be used as a means to some person's ends. This bifurcation is unfortunate because it seems to leave us with no alternative but to categorize everything as either a person or a thing. Yet some of the entities that give rise to the most vexing ethical problems are exactly the ones that do not seem to fit comfortably into either category. For various, different, kinds of reasons, it seems inappropriate to categorize a fetus, a non-human animal, the environment, or an object of great beauty, as a person, but neither does it seem right to say of such things that they are to be valued only as means.

Imagine that you are struggling to finish a project, with the deadline fast approaching. Nearly done, you are about to print out what you have finished when a dialog box appears on your computer screen telling you that you must download and install an update for some piece of software. Frustrated, you try to make it go away, but it keeps reappearing. So you relent and click on ‘Install’, and your screen is filled with small print listing ‘Terms and Conditions’. You do not have time to scroll through the whole thing. So you click ‘Agree’. The installation begins, and you are relieved that it takes only a few minutes. Soon you are back at work and have finished your project.

Most people take it for granted that it's morally permissible to have children. They may raise questions about the number of children it's responsible to have or whether it's permissible to reproduce when there's a strong risk of serious disability. But in general, having children is considered a good thing to do, something that's morally permissible in most cases (perhaps even obligatory).

Is democracy a good thing? Most of us think so. And yet, as Jonathan Wolff here explains, Plato thought democracy was a very bad idea. If you favour democracy (and I'm guessing you do), then your challenge is to explain what, if anything, is wrong with Plato's argument. So can you?

Some argue that genetic engineering and other scientific practices are morally wrong because they are ‘unnatural’. Prince Charles took this line in his 2000 Reith Lecture. But as Mary Warnock here points out, attempts to justify the moral condemnation of a practice on the grounds that it is ‘contrary to nature’ are notoriously difficult to sustain.