Abstract

We maintain that there is something called natural necessity that is involved in the laws of nature -laws are concerned with what must happen, and what could not possibly happen. rather than merely what does and does not happen. Some recent believers in natural necessity, such as Dretske [1977], Tooley [1977,1987] and Armstrong [1978, 1983], have argued that this natural necessity arises from certain relations among the properties of things in our world - they argue that there are relations of “neessitation” holding among universals. We endorse this theory that laws involve reiatiorts among properties of things. Howev- er, we thinlt that more needs to be said about what underlies this relation of necessitation. In this paper we assume that there exist certain complex properties, which we call states of systems, or just states, and we postulate that there are some states that are natural for our world and other states that are non-natural for our world. Given that there does exist a real distinction between natural and non-natural states for our world, there will be a definable kind of natural necessity - there will be a significant sense in which laws really do tell us what must happen and what could not possibly happen.