We distinguish common nouns, proper nouns, and mass nouns. Proper nouns are entities for they name single thing. Common nouns are generally sites for they name collections. And mass nouns, too, are always sites, representing collections. Adjectives specify not only a member of a class but clarify that the noun itself represents a collection.
Sites are the classes and categories of our knowledge.
Like noun phrases they come in two types - parts and wholes, splitting each entity period into two distinct halves. For the past nearly 70 years we have been in a wholistic phase, and now enter a parts phase of knowledge. Parts Wholes Site nouns, like entity nouns, come in both singular and plural forms, suggesting that we will find site artifacts in singular and plural forms. And we do find two large phases of knowledge within each singular and plural period that I call parts and wholes , based on the two kinds of site artifacts. Max Wertheimer beautifully expresses the difference in the knowledge constructed during each of these two phases in his major work on gestalt psychology.