These restrictions may not always comport well with our ordinary language usage. Terms can be complicated noun phrases. This can make working with them a bit cumbersome. All philosophers who study such things as consciousness, folk psychology, and perception are philosophers of mind and psychology. For example, an adjective may appear without a noun or pronoun.
All logicians are rational creatures.
All fish swim. All fish are swimmers. All fish are creatures that swim. Along with a standard form, each type of categorical statement has numerous stylistic variants. In such cases, one must rewrite the variant into the standard form.