These statements are made for the sake of illustrating, not of exhausting, the subject. It follows, however, as an inference from them, that the classification of pronouns is complicated. Even if we knew the original power and derivation of every form of every pronoun in a language, it would be far from an easy matter to determine therefrom the paradigm that they should take in grammar. To place a word according to its power in a late stage of language might confuse the study of an early stage. To say that because a word was once in a given class, it should always be so, would be to deny that in the present English they, these, and she are personal pronouns at all.
The two tests, then, of the grammatical place of a pronoun, its present power and its original power, are often conflicting.
In the English language the point of most importance in this department of grammar is the place of forms like mine and thine; in other words, of the forms in -n. Are they genitive cases of a personal pronoun, as mei and tui are supposed to be in Latin, or are they possessive pronouns like meus and tuus?
Now, if we take up the common grammars of the English language as it is, we find, that, whilst my and thy are dealt with as genitive cases, mine and thine are considered adjectives. In the Anglo-Saxon grammars, however, min and þin, the older forms of mine and thine, are treated as genitives; of which my and thy have been dealt with as abbreviated forms, and that by respectable scholars.
Now, to prove from the syntax of the older English that in many cases the two forms were convertible, and to answer that the words in question are either genitive cases or adjectives, is lax philology; since the real question is, which of the two is the primary, and which the secondary meaning?
[§ 447]. The à priori view of the likelihood of words like mine and thine being genitive cases, must be determined by the comparison of three series of facts.
1. The ideas expressed by the genitive case, with particular reference to the two preponderating notions of possession and partition.
2. The circumstance of the particular notion of possession being, in the case of the personal pronouns of the two first persons singular, generally expressed by a form undoubtedly adjectival.
3. The extent to which the idea of partition becomes merged in that of possession, and vice versâ.