The plain-language article introduced the idea of “chinjutsu.” Here we read it in the original text of Part II, “Sentence Theory,” of Nihon Bunpōron.
What is a “unified thought”?
Before defining the sentence (句, ku) itself, Yamada first explains what a “unified thought” is.
単一なる思想とは一箇の統覚作用によりて之に統一されたるものをさすなり。
(A unified thought refers to that which has been unified, into a single whole, through a single act of apperception.)
The term “tōkaku sayō” (統覚作用) is a Japanese rendering of “Apperzeption,” a concept used at the time by German psychologists like Wilhelm Wundt — the mental function that integrates multiple separate ideas into one coherent whole within consciousness. Yamada borrows this psychological concept to explain why a string of several words comes together as a single “thought,” rather than remaining a scattered collection. Words merely lined up in a row don’t, by themselves, add up to a thought. Some mental act is needed to bind them into one — and that is Yamada’s starting point.
A sentence is a “complete unity” expressing a single thought
Building on this “unified thought,” Yamada then defines the sentence itself.
こゝにいふ一の句とは、単一思想をあらはす一體ならざるべからず、しかもそれ他と形式上獨立したる一完全體ならざるべからず。
(What is here called a single sentence must be a unity expressing a single thought, and moreover it must be a complete unity, independent of others in its form.)
This one sentence states two conditions at once. First, a sentence must be a “single unity” expressing a single thought — this is exactly what happens with a sentence like “the flower blooms,” covered in the plain-language article: several words pointing at a single event. Second, a sentence must be “completely independent” in its form — it must be a unit set off by a full stop, grammatically self-sufficient on its own.
Borrowing a psychological concept to explain grammar
What’s interesting about this passage is that Yamada applies a concept from cutting-edge German psychology of his day (apperception) to explain Japanese grammar. Much of the grammatical research by scholars of Japanese classical studies up through the Edo period had focused on observing and classifying real examples of Japanese. Yamada brought in a new theoretical tool — Western psychology — to give a theoretical account of a question that hadn’t previously been asked head-on: why does a sentence complete itself at all?
Summary
| Point | Detail |
|---|---|
| A unified thought | Coherent meaning content, unified through a single act of apperception |
| The sentence, defined | A unity expressing a single thought, and a formally independent, complete unit |
| Distinctive method | Explains sentence-completeness by borrowing the German psychological concept of “apperception” |
In a nutshell — for Yamada, a sentence wasn’t just words strung together. It was a completed unit, bound into one by the mind’s act of apperception, and independent in form as well.