 Unfortunately, it is tricky to specify what we mean by a “natural” property. For our purposes in this entry, as a first approximation, we might take natural properties to be, roughly, those that figure in scientific theories. Examples would be the properties that figure in biology, economics, psychology, and so on, including the property of being an acid, the property of being deciduous, the property of being inflationary, and so on. More broadly, as a second approximation, we might say that a natural property is such that any substantive knowledge we could have about its instantiation would be empirical. This broader usage would allow us to count the properties of being an automobile and being a lawn chair to count as natural ones. (For discussion of the idea of a natural property, see entries on  moral naturalism  and  moral non-naturalism).