Update: Over on Positive Liberty, the always insightful Tim Sandefur has a highly critical comment on Farber's take on the Ninth Amendment. Yes, I did see the one page in Farber's book where he discusses my work and I share Tim's concerns. Considering he chose to write a whole book on the Ninth Amendment, Farber devotes far too little space to the important issues he raises on this single page. Read the whole thing but here is a taste:
How many other things are wrong with this paragraph? Well, first of all, the text of the Ninth Amendment does not refer to "discrete packages" of rights. It refers to "others retained by the people." The term "others" is undifferentiated! It echoes the Declaration's reference to "among these [rights]"—that is, this text exists specifically to point out the fact that the act of differentiating some rights and setting them aside as discrete packages must not be construed to deny the existence of an undifferentiated (and insusceptible of differentiation) mass of other rights that together make up the concept of liberty. The Ninth Amendment would be self contradictory if it were interpreted in a way that required that all the rights to which it refers be "discrete packages."
Farber's error here is not unlike the error committed by Bork and others, who assume that rights must be identified and specified before they can be accepted as constitutionally recognized entities. The Amendment exists precisely to block such a theory: it exists because liberty is made up of an infinite number of undifferentiated rights, and to cut some out from the herd might lead some people, like Bork and Farber, to assume that only those which have been cut out deserve respect.