本質 and 根本: continuing essence and an underlying issue
Compare an essence beyond numbers or changed form with a root problem and a need to review a system from the ground up.
本質 in a problem and a festival
「数字だけを比べても問題の本質は見えてこない。」 (Comparing numbers alone does not reveal the essence of the problem.) 本質 (ほんしつ) means essence or nature. Numbers alone fail to reveal the problem's essence. Retain the limitation だけ rather than declaring all numerical information meaningless.
「形は変わっても、この祭りの本質は受け継がれている。」 (Although its form has changed, the essence of this festival has been passed down.) The festival's form has changed while its essence has been passed down. Keep the changed form and continuing essence together without specifying the festival's content or a date of change.
A root problem and review with 根本から
「表面だけ直しても、根本の問題は残ったままだ。」 (Fixing only the surface will leave the root problem unchanged.) 根本 (こんぽん) means root or fundamental basis. Fixing only the surface leaves the underlying problem unchanged, so the surface and the problem's roots are distinct.
「制度を根本から見直す必要がある。」 (We need to review the system from the ground up.) The system needs review from the ground up. 必要がある states a need, without reporting a completed reform or a solved problem.
Essence and the level at which to review
The 本質 sentences concern the problem's essence and what continues in the festival despite changed form. The 根本 sentences concern an underlying problem and a fundamental level of review.
Distinguish what makes the object what it is from the level at which it needs examination. The stated need for review remains separate from completed reform or problem-solving.
What do the festival's continuing 本質 and review from 根本 focus on?
Show the answer and why
The first focuses on the essence that continues despite the festival's changed form. The second focuses on the fundamental level of review needed for the system, without a completed reform or solution.