(My footnotes didn't fit within the text limit for comments:)
[1] Of course, the field of "cognitive psychology" is itself just a category :-)
[2] I have witnessed many pointless arguments that spring from the false beliefs that categories are binary and that categories consist solely of defining features. Among such overstretched categories I've seen argued: "conservative", "superhero", and "continent". Even seemingly-straightforward categories as "bachelor" ("unmarried man") run into problems (is a Catholic priest a bachelor?). In fact, the only categories that DON'T run seem to run into problems "at the edges"-- the only categories in which all instances really are cleanly "in" or "out"-- are (a) categories specifically designed as artificial and prescriptive, such as "military ranks" and (b) biological species (but only within a particular region and particular range in time-- once you look evolutionarily over enough time, even those "definitions" and "neat boundaries" break down).
no subject
[1] Of course, the field of "cognitive psychology" is itself just a category :-)
[2] I have witnessed many pointless arguments that spring from the false beliefs that categories are binary and that categories consist solely of defining features. Among such overstretched categories I've seen argued: "conservative", "superhero", and "continent". Even seemingly-straightforward categories as "bachelor" ("unmarried man") run into problems (is a Catholic priest a bachelor?). In fact, the only categories that DON'T run seem to run into problems "at the edges"-- the only categories in which all instances really are cleanly "in" or "out"-- are (a) categories specifically designed as artificial and prescriptive, such as "military ranks" and (b) biological species (but only within a particular region and particular range in time-- once you look evolutionarily over enough time, even those "definitions" and "neat boundaries" break down).
[3] Indeed, I list "nonstandard categories" among my hobbies. Examples: The Nine Nations of North America, alternate categories/theories of "generations".