The most relevant parts for nature-and-ethics, I think, are: 54-56, which are especially good for showing the connection between nature, reason, and ethics in Peter Damian; at 87 (and the whole section as well), esp. where Jordan summarizes how Alan of Lille demonstrates the naturalistic fallacy; after a lot of digressing, some material on Albert the Great at 126 ff.; and a good summary of Aristotle's NE at 132. By the Albert the Great section, it becomes apparent that the relation of pleasure to the natural and the moral is what is really at issue. One should also pick up some Plato on this, e.g. from the Laws, 732e, 836c-e, 838b-839c, passages which seem very pertinent. Jordan and Plato seem to diverge regarding this relation.

Jordan does show convincingly that "sodomy," in the Bible defined as the sins of the men of Sodom, applies to a range of sinful activities rather than specifically homosexual ones. He does not, however, show that homosexual activity is excluded within that range of activities.

But even if Jordan were to show that homosexual activity is not one of the sins of Sodom, the implication for us is merely that "sodomy"--if we would like to be etymologically correct--ought not be used as a term for homosexual activity. If he were to establish that, he would not be establishing that homosexual activity is not a sin. The only implication would be that we should use a different term to describe homosexual sin (as for instance was often done by using the more inclusive term "luxuria," it appears). Since Jordan shows a hermeneutical friendliness to the Bible (which is what motivates his etymological interest in "sodomy" in the first place), he would be hard pressed to do away with passages of similar brevity in which homosexual activity is specifically labeled as a sin. (In fact he ignores these passages entirely, as the authors he reads do not, which decimates the value of his arguments around pp. 166 ff.)

Regarding the Middle Ages, even if "sodomy" had been constructed incorrectly as a term for homosexual activity and similar sexual sins, the idea of those sins was not constructed. His interest turns out to be merely etymological through page 40. For most of the remainder of the book, Jordan moves to "invention" in the rhetorical sense, finding all the different ways that sodomy was discussed--seldom engaging the arguments, as though he is having enough fun repeating all the unsayable words.

On 42 and towards the end, he unfairly objects to the use of places and place-names as symbols, calling this an "essentialism" that is "antihistorical." This hermeneutical prejudice is untenable, and not just in the case of Sodom. One might say that "homophobia" is also one of those words that is used as "an attack upon a [supposedly] malignant essence" (43, cf. 167-68). If Jordan really is attacking the whole system of applying abstract words to sets of activities, he loses the ability to make many of his own points as well.