Aristotle was skeptical about Plato's "Ideas" or "Forms" that a demiurge used in the creation of things, but Aristotle did accept the idea of a "telos" or purpose, his "final cause." For artifacts, the telos is put into the object by the artificer. For living things, Aristotle thought the telos was an internal property that he called entelechy, from en-tel-echein - having a telos within.

Over the centuries, some philosophers have hoped to identify various essences that are essential components of various kinds of things. In modern philosophy, there is talk of "natural kinds," which suggest that each "kind" has one or more properties that are essential to being that kind.

John Locke was skeptical about essences in general, like the Platonic Ideas, being used to make up the essence of an individual

’Tis true, there is ordinarily supposed a real Constitution of the sorts of Things; and ’tis past doubt, there must be some real Constitution, on which any Collection of simple Ideas co-existing, must depend. But it being evident, that Things are ranked under Names into sorts or Species, only as they agree to certain abstract Ideas, to which we have annexed those Names, the Essence of each Genus, or Sort, comes to be nothing but that abstract Idea, which the General, or Sortal (if I may have leave so to call it from Sort, as I do General from Genus,) Name stands for. And this we shall find to be that which the word Essence imports, in its most familiar use.

(Essay Concerning Human Understanding, III.iii.15)

In information philosophy, identity depends on the total information in an object or concept. We can "pick out" the intrinsic information as that which is "self-identical" in an object – the "peculiar qualifications" of the individual. This suggests a precise definition of the "essence" of an object, what is "essential" about it.

A subset of the intrinsic information may be essential with respect to (qua) some concept of the object. As Edmund Husserl emphasized, our concepts about objects depend on our intensions, our intended uses of the object, which give it different (pragmatic) meanings. We can say that an essence is the subset of an object's information that is isomorphic to the information in the concept. These essences are subjective, but we can define an objective essence as the total intrinsic information.

Two numerically distinct objects can be perfectly identical (x = x) internally, if their intrinsic information content is identical. Relational (extrinsic) information with other objects and positions in space and time is ignored. The Greeks called intrinsic information pros heauto or idios poion. Aristotle and the Stoics called this the peculiar qualities of an individual. They may be loosely considered the "essence" of the individual.

They distinguished these peculiar properties from the material substrate, which they called hupokeimenon, the "underlying. Extrinsic information is found in an object's relations with other objects and space and time. The Greek terms were pros ta alla, toward others, and
pros ti pos echon, relatively disposed. Aristotle would have called these relative properties accidentals (symbebekos), that play no role in the essence.

Even two distinct objects can be considered essentially the same if they of the same Sort or of a natural kind.

Natural kinds may be described as sharing an essence, or being relatively identical qua that essence, which may be a single property or some bundle of properties.

Natural kinds are sometimes said to "carve Nature at its joints," as Plato put it in the Phaedrus.