  The idea behind this reasoning is that if we have to agree that some reasons depend on desires, then we should give serious consideration to the theory according to which all reasons do, as being simpler and more explanatory than the theory according to which some reasons derive from our desires but others do not. This may even provide a promising analytical hypothesis about what claims about reasons mean, or reductive hypothesis about what reasons are. This kind of argument is anticipated by Williams’ claim that the issue is whether there are both internal and external reasons, or internal reasons only (1979; see also Schroeder 2007b). We now discuss three kinds of externalist objection to this argument.