Now, if normative principles and guiding purposes can be gleaned from our reflections on nature, there would seem to be no truth more obvious than that human sexuality is oriented by its nature toward uniting man and woman, with a view to procreation and family life. If nature cannot tell us that, then it cannot tell us anything. It is completely mute, and human beings are utterly left adrift to invent themselves according to whatever standards they like. This is nihilism, and this unfettered autonomy is in fact what the most consistent proponents of same-sex marriage admit they are after.