Given the abundance of disordered proteins in cells, the physiological milieu offers ample opportunities for interactions that promote disorder-to-order transitions, prompting researchers to ask whether free disordered proteins ever exist in cells, or whether they only occur as complex-bound, ordered entities.
Such quantifiers are called "second-order". Quantifiers that range over sets of second-order entities are said to be "third-order," and so on.
Lyons (1977: 442 445) distinguishes three types of entities: first-order, second-order, and third-order entities.
Outer forces of lower-order entities are inner forces of higher-order entities: for instance, outer forces of nuclei are inner forces of atoms (A.34b).
Third-order entities are abstract; they are outside both space and time.
On the same basis Quine would, no doubt, have accepted that IFL is only committed to first-order entities.
Second-order entities are events, processes/activities, and states; they are what are referred to as "states of affairs".
Generally speaking, first-order entities are physical objects such as animals, people, plants, artifacts, e.g., dog, woman, tulip, and car.
But this is not available in Chinese, where existence of second-order entities has to be conveyed through processes.
