Return to Entity

This term [entity] may be used in several senses. If you speak in the primary sense, "entity" has to be defined ostensively—that is to say, by pointing. I can, however, give you three descriptive characteristics essential to the primary, philosophic use of the term, according to Objectivism. This is not a definition, because I'd have to rely ultimately on pointing to make these points clear, but it will give you certain criteria for the application of the term in the primary sense . . . .

1. An entity means a self-sufficient form of existence—as against a quality, an action, a relationship, etc., which are simply aspects of an entity that we separate out by specialized focus. An entity is a thing.

2. An entity, in the primary sense, is a solid thing with a definite boundary—as against a fluid, such as air. In the literal sense, air is not an entity. There are contexts, such as when the wind moves as one mass, when you can call it that, by analogy, but in the primary sense, fluids are not entities.

3. An entity is perceptual in scale, in size. In other words it is a "this" which you can point to and grasp by human perception. In an extended sense you can call molecules—or the universe as a whole—"entities," because they are self-sufficient things. But in the primary sense when we say that entities are what is given in sense perception, we mean solid things which we can directly perceive.

Leonard Peikoff,
The Philosophy of Objectivism lecture series, Lecture 3