He who affirms must prove.

Explanation

(English-origin maxim.) The party who makes an affirmative claim must sustain it with evidence; the opposing party is not required to disprove what has not first been proved.

Where this applies

• A plaintiff claims the defendant broke a contract but offers no evidence of the agreement or the breach — the court dismisses because the one who makes the claim must prove it.
• A government agency says a business owes back taxes but produces no records showing what's owed — the business isn't required to disprove a claim that was never proved in the first place.
• A neighbor accuses you of building your fence on his property — it's his job to bring a survey or deed showing the true boundary, not yours to prove where your own fence sits.