This morning, like every morning, I had some coffee. I wasn’t thinking of it in quite these terms, but “cogntive enhancement” was part of my aim. I daresay I use coffee responsibly, but in doing so I presuppose nothing in particular about “mental life considered as a whole.” I recently bought new running shoes, which I certainly hope will (responsibly!) enhance my ability to run, but I do not therefore presuppose that the single good of physical life as a whole is to run as fast as possible. You can do lots of things with your body. You can do lots of things with your mind. Why not do them a little better?