 This seems to get a number of cases right. The reason that questions like “What kind of animal is named ‘Fido’?” or “What is a Sheltie?” trigger “X”, meaning dog, is that dogs are able to trigger “X”s. Foxes only trigger “X”s, meaning dog, because dogs are able to trigger them. Moreover, it appears to solve the disjunction problem. Suppose we have a ‘dogs cause “X”s’ law and a ‘dogs or foxes cause “X”s’ law. If one breaks the ‘dogs cause “X”s’ law, then one thereby breaks the ‘dogs or foxes cause “X”s’ law, since the only reason either dogs or foxes cause “X”s is because dogs do. Moreover, if one breaks the ‘dogs or foxes cause “X”s’ law, one does not thereby break the ‘dogs cause “X”s’ law, since dogs alone might suffice to cause “X”s. So, the ‘dogs or foxes cause “X”s’ law depends on the ‘dogs cause “X”s’ law, but not vice versa. Asymmetric dependency of laws gives the right  results.[9]