Fetching details from the dictionary...
insisting (unreasonably); obstinate insistence; far-fetched argument; arguing against all reason
彼は自分の非を認めず強弁した。
He insisted unreasonably without admitting his fault.
強弁しても事実は変わらない。
No matter how stubbornly you argue, the facts won't change.
証拠を前にして強弁は通用しない。
Obstinate arguments don t hold up before evidence.