人生, 生涯 and 一生: life experiences and lifetime scope
Compare wanting a sea voyage and looking back on life with lifelong dedication, never leaving a town, and a prediction about remembering. Preserve the overlap between 生涯 and 一生.
人生 concerns experiences and reflection
人生 (じんせい) means life. In “人生で一度は長い船旅をしてみたい。” (“I want to take a long sea voyage at least once in my life.”), the speaker wants to take a long sea voyage at least once in life. してみたい expresses a wish to try it, rather than a voyage already completed.
In “祖父は自分の人生を振り返り、静かに笑った。” (“My grandfather smiled quietly as he looked back on his life.”), the grandfather smiled quietly while looking back on his life. These scenes focus on the experiences someone wants and the life someone recalls.
生涯 places an action within a lifetime
生涯 (しょうがい) means lifetime or life. In “彼女は生涯を教育に捧げた。” (“She devoted her life to education.”), she devoted her life to education. The wording describes lifelong dedication without specifying every educational result or the length of her life.
In “祖父は生涯この町を離れなかった。” (“My grandfather never left this town in his lifetime.”), the grandfather never left the town in his lifetime. Preserve the negative 離れなかった; changing it to a departure would reverse what the sentence reports.
一生 overlaps with 生涯 in lifetime scope
一生 (いっしょう) means an entire life or lifetime. In “この日の感動は一生忘れないだろう。” (“I will never forget the emotion of this day for as long as I live.”), the speaker predicts never forgetting the emotion of that day for as long as they live. 忘れないだろう looks ahead, rather than reporting memory across an already completed lifetime.
In “祖父は一生を教育の仕事に捧げた。” (“My grandfather devoted his entire life to education.”), the grandfather devoted his entire life to education. Both this 一生 example and the 生涯 example can describe lifelong dedication to education. Their lifetime meanings overlap, even though the people in the examples differ.
Can 生涯 and 一生 overlap when describing a life devoted to education?
Show the answer and why
Yes. 彼女は生涯を教育に捧げた and 祖父は一生を教育の仕事に捧げた both describe lifelong dedication to education. They have different subjects, but the lifetime scope of the two expressions can overlap.