According to interest theorists of rights, rights function to protect the right-holder's interests. True. But this leaves a lot unsaid. Most saliently here, it is certainly not the case that every agent who stands to benefit from performance of a duty gets to be a right-holder. For a theory to allow this to be the case—to allow for an explosion of right-holders—would be tantamount to a reductio thereof. So the challenge for interest theorists is to respect the core of the interest theory while delimiting the set of right-holders in a principled manner. The foremost explicit attempt to do this has invoked Bentham's test. Predictably, invocation of this test has come under attack, with the ultimate aim of challenging the interest theory itself. My purpose in this paper is to render Bentham's test as clearly and accurately as possible. Doing so will raise issues of modality—ultimately in rendering Bentham's test's logical form. Ultimately a core attack on Bentham's test falls away, and, to that extent, the interest theory remains standing as a promising theory of rights.