Harry Chalmers

Commonsense morality holds that monogamy is morally permissible. In this paper I will challenge this, arguing that monogamy is in fact morally impermissible. First I’ll argue that monogamy’s restriction on having additional partners seems analogous to a morally troubling restriction on having additional friends. Faced with this apparent analogy, the defender of monogamy must find a morally relevant difference between the two kinds of restriction. Yet, as I’ll argue, there seems to be no such morally relevant difference, for the standard defenses of monogamy all fail. I take this to be evidence that monogamy’s restriction on having additional partners is in fact morally analogous to a restriction on having additional friends. Just as a restriction on having additional friends is immoral, so, too, is monogamy’s restriction on having additional partners.

Monogamy, I’ve argued, faces a pressing problem: the difficulty of finding a morally relevant difference between its restriction on having additional partners and a restriction on having additional friends. To the extent that we’d find a restriction on having additional friends morally troubling, that puts pressure on us to judge the same about monogamy. This argument, however, has recently come under attack by Kyle York, who defends monogamy on grounds of specialness, practicality, and jealousy. In this paper I’ll argue that, pace York, these defenses of monogamy all fail.