Do 形容詞 have a 未然形 in Classical Japanese?

Question

I was reading Eiríkr Útlendi's answer about -い vs. -き in 形容詞 and noticed that he identified -く as the 未然形 of 形容詞. When I studied classical Japanese, though, I was taught that 形容詞 lack a 未然形 (and also lack a 命令形, of course).

This jives with my (probably poor) intuition about how 形容詞 conjugate - you can't say *美しくず or *美しくぬ for the negative of 美し - you have to say 美しくあらず or 美しからぬ or something like that (i.e. using the 連用形, which is 美しく, adding an あり, and then tacking a negation 助動詞 onto the 未然形 of あり, which is あら).

Are there multiple schools of thought on whether or not 形容詞 have a 未然形? The textbook I used was 新編文語文法 by 大野晋, in case that helps.

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UPDATE: I found my textbook; it states the following in the section on 形容詞の活用の種類 (p. 30): for the ク活用, we have two patterns of conjugation (未然・連用・終止・連体・已然・命令):

 1.　　 〇　　　　　―く　　　　　―し　　　　　―き　　　　　―けれ　　　　 〇
 2.　　―から　　　　―かり　　　（―かり）　　　―かる　　　（―かる）　　　―かれ

Likewise, we have two patterns of conjugation for シク活用:

 1.　　 〇　　　　　―しく　　　　―し　　　　　―しき　　　　―しけれ　　　 〇
 2.　　―しから　　　―しかり　　（―しかり） 　　―しかる　　（―しかる）　　―しかれ

The textbook does not specifically name the (2.) conjugations as the カリ活用 and シカリ活用, but does mention them. In any case, the textbook specifically claims that in their "bare" form (without あり), 形容詞 do not have a 未然形 (p. 31; emphasis added):

「ク活用」「シク活用」のいずれの場合も、本来の活用は「〇・く・し・き・けれ・〇」「〇・しく・し・しき・しけれ・〇」で、未然形・命令形がなかった。それでは助動詞に続かず不便なので、のちに、それを補うために、連用形のあとにラ変動詞「あり」をつけて、「高く＋あり→高かり」のように熟合させたのが[the (2.) conjugations]である。これによって未然形・命令形を補うと共に、助動詞との接続が自由になった。

Answer 1

The use of the 未然形 is quite limited. As 形容詞 don't conjugate like verbs, it's hard to say they have the 未然形.

But as far as I know, there are several theories claiming 形容詞 do have 未然形:

1. く is the 未然形. ～くば resembles 動詞未然形＋ば, which is the conditional from.

2. く is the 未然形. ～くない resembles 動詞未然形＋ない, which is the negative form.

3. け is the 未然形. ～けく resembles 動詞未然形＋く, which is known as the ク語法.

4. から is the 未然形. ～からず resembles 動詞未然形＋ず.

5. け is the 未然形. ～けむ resembles 動詞未然形＋む, which is the future/volitional form.

1 is just a coincidences. は, ずは, ずんば, etc. have the same function, too.

So is 2.

3 doesn't etymologically make sense to me.

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If you look at the auxiliaries that accept the 未然形, you will find they are full of irregularities. e.g.

ない：（サ変）しない；（カ変）こない；（一段）みない、

まい：（サ変）しまい／すまい／するまい／せまい；（カ変）こまい／くまい／くるまい；（一段）みない、みるまい；（二段）うけまい／うけるまい

べし, す and る are irregular too. ず, ぬ and む are relatively regular, though.

Except ず, ぬ and む, you can't derive the proper form for most regular verbs solely by attaching the auxiliary to the 未然形 of the verb. The regularity of ず might be simply because 未然形 was defined as the form required by ず, as its name implies.

Answer 2

I am of the opinion that the 未然形 actually does not exist as a true form, in either Modern or Classical Japanese.

Unlike, say, the 已然形 and 連用形, the 未然形 never appears on its own. In addition, it only has a distinct conjugation pattern for 四段 (and "relatives" ラ変, ナ変) verbs.

What the 未然形 actually is in, say, 二段 verbs is extremely confusing. In this case, it is identical to the stem of 二段 verbs, which ends in a vowel.

The only usage of the 未然形 is to attach stuff after it. This is in contrast with the other 形s which all have uses by their own (已然形 is arguably the 連用形 of the potential in Modern Japanese) no matter in inherent meaning or constructions like 係り結び.

So in my opinion, 未然形 is a device to attach random stuff directly onto the stem, since none of the semantic scopes of the other 形s fit. Since we cannot directly attach things onto consonant in Japanese, we must insert -a for 四段 type verbs.

(Note that I do not prescribe to the view that all 形s are simply epenthetic vowels and the suffix たり ex. is actually -(i)tari. This requires awkward rules mandating deletion in 二段 verbs, ignores the semantic classes exhibited by, say, suffixes using 已然形 and 連用形, and are often completely ignorant of etymology (i.e. 連用形＋ぬ cannot possibly be -inu since ぬ is likely to be the proto-Japonic copula, and gerund+copula (することがある) fits the meaning very well))

Therefore, adjectives do not have a 未然形 since they are not 四段動詞.

Answer 3

There are two conjugation patterns for 形容詞, as shown in the Japanese Wikipedia article here. The second カリ活用 pattern has more distinct forms. The 未然形 with negative here would be ~からず, or with the presumptive, ~かろう. I'm less familiar with these forms, but the 命令形 persists even in modern Japanese in phrases like 遅かれ早かれ "sooner or later".

Past there, whether to consider the く ending to be just the 連用形, or both the 未然形 and the 連用形, might be a matter of scholarly argument.

(Note again that this would be for classical Japanese, not modern.)