述べる and 主張: stating something and the claim stated
Read the difference between an act of stating reasons or witnessed events and the claim expressed. 主張を述べる combines an action with its content.
Reading what was stated
述べる (のべる) means stating or describing content in speech or writing. In 「代表は計画に賛成する理由を述べた。」, the representative stated reasons for supporting the plan.
「目撃したことを順番に述べてください。」 requests an account of what was witnessed, in order. The witnessed events are the content; the request does not establish that the account is complete.
A claim as someone’s position
主張 (しゅちょう) refers to a claim or position. 「会議では根拠を示しながら自分の主張を述べた。」 describes stating one’s position while presenting supporting grounds.
「双方の主張が食い違い、話し合いは長引いた。」 says the discussions dragged on because the two sides’ claims conflicted. The existence of a claim does not establish its truth.
Why both appear together
In 主張を述べる, 主張 is the content and 述べる is the act of expressing it. Their combination shows that they need not replace each other.
Not every statement of reasons, circumstances, or witnessed events must be treated as a claim. Identify the position expressed separately from the act of stating the content.
What is stated in 「会議では根拠を示しながら自分の主張を述べた。」?
Show the answer and why
The speaker’s own claim or position. 主張 names the content, 述べた names the act, and 根拠を示しながら says that supporting grounds were presented while it was stated.