整理 and 整頓: organizing thoughts and arranging physical objects
Compare organizing thoughts or papers with tidying objects on a desk. Read content structure and physical arrangement while allowing overlap for goods.
An action taken to organize thoughts
整理, read せいり, means organize or sort out. 考えを整理するため、結論と理由を紙に書き出した。 says that someone wrote the conclusion and reasons on paper to organize their thoughts.
Writing the conclusion and reasons is the completed action. The purpose given by 整理するため does not establish fully organized thoughts or a tidied desk.
Tidy the physical arrangement
整頓, read せいとん, means tidying or organization. 作業を終えたら机の上を整頓しておこう。 suggests tidying the desk when the work is finished.
作業を終えたら is a condition and 整頓しておこう a suggestion. Do not turn finishing work and tidying into already completed events.
The papers' result and the tools' state
机の資料を整理したら、探していた手紙が見つかった。 says that organizing the papers on the desk led to finding the letter being sought. Both organizing and finding are stated.
道具が種類ごとに整頓され、探しやすくなった。 says that the tools were organized by type and became easier to find. 整理 and 整頓 can overlap for goods; actually finding a particular tool is separate information.
What purpose and completed action are given by 考えを整理するため、結論と理由を紙に書き出した。?
Show the answer and why
The purpose is organizing thoughts, and the completed action is writing the conclusion and reasons on paper. It does not automatically establish a tidied desk or fully organized thoughts.