Assessing evidence and explanations in Japanese

Level B2

Assessing evidence and explanations in Japanese

This lesson teaches you to ask what supports a claim, notice its assumptions, and weigh other explanations. You’ll practise distinguishing a relationship between changes from proof that one caused the other. Japanese signals formality mainly through sentence endings and phrasing, rather than a formal and informal equivalent of English “you.”

Words for evidence and explanations

Ask what supports a claim

Use 裏付ける to say that evidence supports a claim, and state what the evidence can cover. A polite question is “どんな証拠がありますか。”; a casual version is “何を根拠にしてるの？” English uses the same “you” in both situations, while Japanese changes the sentence ending and phrasing to signal politeness.

資料は説明を裏付けていますが、期間分しかありません。

Point out an assumption

Use 仮定 to name an idea being taken for granted. For example: “どちらの月も建物が同じくらい使われていたという仮定ですね。” The polite ですね presents the point in a measured way; casually, “仮定を置いてるんだね” uses the plain ending んだね. Japanese does not need an explicit “you” here.

Separate association from cause

関連 means there is a relationship between two changes; it does not prove a causal relationship. Say “関連がありますが、まだ因果関係を立証できていません” when the cause has not been established. In the casual example, “立証しているわけじゃないよ” gives the same caution with plain forms; English makes this distinction with wording rather than sentence endings.

Qualify a possible cause

Use 原因の一つかもしれません to say something may be one of several causes, not the proven cause. Add the limit: “どのくらい影響したかはまだ分かりません。” The polite forms かもしれません and 分かりません suit a careful discussion; the casual versions かもしれない and 分からないよ fit familiar conversation.

要因も結果の原因(げんいん)の一つかもしれませんが、どのくらい影響したかはまだ分かりません。

Compare plausible explanations

The formal question “気温が上がったからだと考えるほうが、もっともらしい説明になりませんか” invites the listener to consider an alternative without asserting it as fact. Informally, “...もっともらしい説明かもしれないね” marks it as a possibility. Japanese can leave the listener unstated, so do not add a pronoun just because English uses “you” or “we.”

原因についての説明と考えるほうが、もっともらしい説明になりませんか。

Review the evidence politely

This exchange uses polite endings such as ありますか, ありません, and ません to keep a measured tone. The speakers question the evidence and assumption, then say plainly that association has not yet established causation. Use this style in a professional or more distant conversation; Japanese conveys the formality through phrasing and endings, not a formal second-person pronoun.

Review the evidence casually

This exchange uses plain and casual endings such as してるの, だけだよ, and 分からないよ. The speakers still qualify their conclusions carefully; casual grammar does not turn a possibility into a fact. Use this style with people you are close to or normally speak with casually.

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