1To discuss a topic — to state one's views on it or treat it in detail.
専門家たちがその問題を論じるために会議を開いた。
Experts held a meeting to discuss the issue.
この本は現代社会の課題を幅広く論じている。
This book discusses the challenges of modern society in a broad way.
まだ論じるべき点がいくつか残っている。
There are still a few points left that need to be discussed.
2To argue or dispute — to present reasoning for or against something.
彼らはその理論の是非について熱心に論じ合った。
They argued passionately with each other about whether the theory was right or wrong.
複数の研究者がその結論に反対の立場から論じた。
Several researchers argued against that conclusion.
3Used mostly in negative sentences to express whether something is worth taking seriously or raising, as in 論じるまでもない ("not even worth discussing").
そんな些細な問題は論じるまでもない。
Such a trivial matter isn't even worth discussing.
確たる証拠がない以上、その点を論じる意味はない。
Without solid evidence, there's no point in arguing that point.