 The distinction between intrinsic and extrinsic properties plays an essential role in stating several interesting philosophical problems. Historically, the most prominent of these has to do with notions of intrinsic value. G. E. Moore (1903: §18) noted that we can make a distinction between things that are good in themselves, or possess intrinsic value, and those that are good as a means to other things. To this day there is still much debate over whether this distinction can be sustained (Feldman 1998, Kagan 1998), and, if it can, which kinds of things possess intrinsic value (Krebs 1999). In particular, one of the central topics in contemporary environmental ethics is the question of which kinds of things (intelligent beings, conscious beings, living things, species, etc) might have intrinsic value. While this is the oldest (and still most common) use of the intrinsic/extrinsic distinction in philosophy, it has not played much role in the discussions of the distinction in metaphysics, to which we now turn.