The purpose of this work is to provide a metaphysical theory of properties and scientific laws. This sentence will require some unpacking. By a ‘metaphysical’ theory here, I mean a theory of what exists in the world. In this investigation I am primarily concerned with a theory of what properties there are in the world and the role they play in scientific laws. This may be contrasted with a linguistic or epistemic project, as it is not primarily about our language, ideas, or theorizing but rather about what is in the world itself. Properties are what we may pre-philosophically think of as the characteristics of an object: such as its height, weight, color, etc. Investigation may cause us to doubt whether some of these pre-philosophical properties are genuine in a metaphysical sense: whether or not the property is actually present as a feature of the world. By scientific laws, I mean the statements we make in the form of exceptionless generalities about the world within the sciences. Here I do not mean to evaluate how science comes about these generalizations, only that they do and how these generalizations may be grounded in a metaphysical theory of properties. The link between these two things: properties and scientific laws, comes about because our scientific laws prominently feature properties: velocity, temperature, charge, viscosity, etc.
After a review of some of the theories currently proposed in the philosophical literature along with a treatment of some of the problems that arise out of these theories, I will propose a new theory. This theory, entitled ‘Constitutive Trope Theory’ is a form of a ‘bundle trope theory’ as it proposes that objects in the world are composed entirely out of particularized properties. However, rather than proposing a primitive relation that does the bundling, this theory will propose that, at least for the objects we are familiar with, properties arise out of relations between lower-level properties that instantiate them. For example, a mammal may exist because of the relationship between the organs that lead to its unique properties as a mammal. Those organs in turn exist because of relationships between their cells that lead to their unique properties as a particular kind of organ. And so on down the chain until we hit ‘foundational properties’: properties which are not dependent on any other properties for their existence. I will say very little about these properties as I do not believe that any such properties have currently been found and will argue that such theorizing is premature before such properties have been empirically identified. Following this account, I will consider some of the problems that must be overcome and some final considerations in favor of this theory over other competing theories of properties and scientific laws.