 Non-Humeans, by contrast, take fundamental properties to include modal properties, such as nomic necessitation relations, dispositional essences, or causal properties. For non-Humeans causal features can be among the fundamental building blocks of the world. Some non-Humeans hold that the dynamical laws of physics are fundamentally causal laws in virtue of which earlier states of a system or of the world produce later states (Maudlin 2007). Others maintain that objects possess fundamental dispositions, capacities, or essences that are causal in nature (Cartwright 1989; Bird 2007).