Substance and Entity

Entity is a concept, and, like substance, is a tool by which we grasp reality. Reality in itself is what it is whether we conceive of things as entities, or substances, or existents.

Consider the Chinese language. Unmodified nouns in Chinese are always substances, never entities. In English we have what are called count nouns (entities) such as 'dog' and 'tree' and we have mass nouns such as 'gold' and 'grass' and 'rice.' Count nouns speak of individuals, and can be counted. Mass nouns speak of substances, and cannot. One can own 'a dog' or cut down 'three trees' but one does not own 'a gold' or cut down 'three grasses.' Mass nouns must be quantified with a quantifying word which serves as a unit. One can own a piece of gold or cut a blade of grass. In Chinese, except for quantifiers, all nouns are inherently mass nouns.

From Wikipedia:

Chinese nouns require counters (also termed measure words or classifiers) in order to be counted. That is, when specifying the amount of a countable noun, the counter has to agree with the noun. Hence one must say "兩頭牛/两头牛 two head of cattle", not two cows, with "頭/头 head" being the unit of measurement, or measure word. This phenomenon is common in East Asian languages. (In English, some words, as in the cited example of "cattle", are often paired with a noun used much like the Chinese measure word. Bottle in "two bottles of wine" or piece in "three pieces of paper" are examples; one does not typically say, "two wines" or "three papers", unless talking about types of wine or academic research respectively.)

Substances and entities are different ways of speaking of things that exist physically no matter how we do or do not think of them. One can say look at that body (entity) or look at that flesh (substance). A person can be a "waste of flesh." Now, of course, humans are, by their nature, individuated. It might be hard to say whether a plant with three trunks is a sparse bush or three merged trees. But a living human is an individual, even if the living individual has a parasitic conjoined "twin."

Rand speaks of units as the way by which we measure substance as if it were entity. Chinese, and many other languages do this with all existents by speaking of one body of man and one grain of rice.

Psychoepistemologically, entities are prior, since the first given is the body, which is an entity. We experience existence as a body within a world of bodies. Everything of which we are aware is a body, or exists in relation to a body. It is the bodily, and not material or substance which is given.

In nature, the term which we use depends on scale. Prospectors find nuggets of gold which are big enough to be treated as entities, and they find gold dust, which, due to matters of scale, is treated as if it is a substance. But substances are always definite. The always have some definite extension, some definite amount, even if that amount is so fine grained that we find it difficult to measure. In the end, we find some whole number of atoms of gold, we do not find three and 3/4 of an atom of gold.

Everything that exists is some definite thing. To that extent, we can say that all existents are entities – or are substances comprised of entities. There is a finite number of molecules of gas in a gust of wind. To speak of the molecules as individuals is perverse so far as every day usage is concerned. At our scale, treating air as a mass noun makes sense. But the perspective of language can change according to the needs of mental economy. Whatever our needs, the underlying reality is what it is regardless.