Humean interpretations claim that laws of nature merely summarize events. Non-Humean interpretations claim that laws force events to occur in certain patterns. First, I show that the Lewis/Ramsey account of lawhood, which claims that laws are axioms or theorems of the simplest strongest summary of events, provides the best Humean interpretation of laws. The strongest non-Humean account, the scientific essentialist position, grounds laws of nature in essential non-reducible dispositional properties held by natural kinds. The scientific essentialist account entails that laws (...) are a posteriori necessary truths. After showing that these are the best Humean and non-Humean accounts, I demonstrate that the Lewis/Ramsey account is better equipped for interpreting dispositions and counterfactuals. One distinction between the two accounts is whether counterfactuals, whose antecedents are physically possible, sometimes require closest worlds with different laws than the laws of the base world. On the Lewis/Ramsey account non-legal worlds will be necessary. If laws are merely summaries of events that occur then a world where the events are drastically different will often have different laws. The scientific essentialist, however, must demand that laws are the same in counterfactual reasoning because she grounds counterfactual reasoning in the essential dispositional properties of natural kinds. Recently, problems have developed for counterfactual analysis of dispositions due to finkish dispositions, mimicked dispositions, and masked dispositions. These difficulties have led some to abandon reductive accounts of dispositions. Doing so makes positions like scientific essentialism tenable. Yet, while scientific essentialism demands that dispositional properties cannot be reduced to categorical properties, the Humean has the opposite commitment. If dispositional properties are primitives in our ontology, then there is a stronger tie between events than Humeans admit. So, another major disagreement between these accounts is whether dispositions can be reduced. After examining why many attempts at reducing dispositions have failed, I offer one suggestion of how to reduce dispositions and demonstrate that keeping dispositional properties as primitives in our ontology is worse than the solution I offer. (shrink)

Almost everyone agrees, under some interpretation, that a world is nomologically accessible if and only if it obeys the laws of the base world. This surface agreement, however, has led many to attach little importance to different interpretations, thereby conflating two distinct concepts of nomological accessibility. According to the Shared Law Account (hereafter SL), a target world is nomologically accessible from the base world if, and only if, all and only the laws of the base world are laws at the (...) target world. The Compossible Events Account (hereafiter CE) holds that a target world is nomologically accessible from the base world if, and only if, all events of the target world are compossible with the laws of the base world. After demonstrating that these accounts are distinct, I shall show that the distinction matters. Not only is the correct modal system for nomic necessity determined by which characterizes accessibility, but some arguments against Humean supenfenience depend upon SL. In the final section I show that CE is the correct interpretation. (shrink)