 Determination involves the idea that the requirements associated with one thing include the requirements associated with another; and although properties are requiremental on their face, particulars are not. Hence the need for a notion of individual essence, where essential properties of a thing are those it cannot exist without. [T]he essence of a thing is supposed to be a measure of what is required in order to be that thing. Thus if more is required to be \(y\) than to be \(x\), this should be reflected in an inclusion relation between their essences: