 To say that you have a right to pick up the shell is to say that you have no duty not to pick it up. You will not be violating any duty not to pick up the shell should you decide to do so. Similarly your right to sit in an empty seat in the cinema, and your right to paint your bedroom red, are also privileges. Privilege-rights mark out what their bearer has no duty not to do. When US Presidents invoke “executive privilege,” they deny an assertion that they have a duty not to withhold evidence: they assert a Hohfeldian privilege. Similarly, a license (to drive, to perform surgery, to kill) endows its holder with a privilege to engage in the licensed activity. Someone with a license to drive has no duty not to operate (specified kinds of) motor vehicles (in particular ways).