What arguments are used to answer this question? Does it stem from a lack of agreement over how to define a pronoun?
Essentially, yes. Even your own Wikipedia quote has the infamous : (reproduced here for emphasis)
Strictly speaking, pronouns do not take modifiers, but Japanese daimeishi do: 背の高い彼 se no takai kare (lit. tall he) is valid in Japanese.
Also from Wikipedia, Japanese Pronouns (
In linguistics, generativists and other structuralists suggest that the Japanese language does not have pronouns as such, since, unlike pronouns in most other languages that have them, these words are syntactically and morphologically identical to nouns. As functionalists point out, however, these words function as personal references, demonstratives, and reflexives, just as pronouns do in other languages.
If so, under which definitions does Japanese have and not have pronouns?
Under the common definition (which I will regard as the dictionary definition), Japanese definitely has pronouns.
From the Merriam-Webster online dictionary, a pronoun is
any of a small set of words in a language that are used as substitutes for nouns or noun phrases and whose referents are named or understood in the context
And, from the Cambridge online dictionary, it is
a word that is used instead of a noun or a noun phrase:
Clearly, any Japanese pronoun satisfies these conditions.
So, why do some consider Japanese pronouns not pronouns?
All languages have at least some 1st person and 2nd person pronouns. Those are nearly always irregular - for example, if they distinguish singular and plural, they form the plural differently than nouns, or they may even have multiple "kinds" of plural; and they form a closed set of grammatical words. The grammatical irregularity helps to freeze the membership in the class of pronouns.
Japanese stands out by apparently being able to produce new pronouns from verbs and nouns while retaining their regular morphology. Pronouns are not such an exclusive club like in most other languages.
Another way to look at it is to interpret your question as a question about the meaning of the English word "pronoun". English pronouns can't take modifiers, and Japanese 'pronouns' can, therefore Japanese pronouns aren't actually pronouns in the Anglo-centric sense of the term.
That Anglo-centrism can be as minimal as requiring pronouns to be grammatical words as opposed to standard lexical items. In English, we need a class of words labeled 'pronoun' for grammatical purposes (e.g. the aforementioned inability to use modifiers with them). Japanese pronouns, as true nouns, do not need a separate class. That is to say, in Japanese, pronouns are nouns in every sense, and so they don't exist separately.
Huge thanks to Jirka Hanika for expounding on my last section.