以西方倫理學理論為基礎，進而嘗試系統性地建構墨子關於兼愛的理論是許多研究者採用的研究方式。然而，本文發現墨子在面對批評兼愛者與認同兼愛者之時，採用了不同的論說方式。面對批評者，墨子以反證其論點不能成立的辯論手法促使其認同兼愛；面對認同者，則採用互利原則以增強其實踐兼愛的信念。不過，用以擊破反對者論點的辯論內容以及增強實踐信念的互利原則，仍不足以窺見兼愛的實踐精神。本文從墨子實踐兼愛的相關文獻中，揣摩其精神境界：發現在此實踐精神中，兼愛本身即為價值根源，兼愛的行為本身是義；而不論利己或利他的效益，都只是兼愛行為所產生的附加價值。以兼愛的價值認同所引發的實際行動本身就是義，因現實環境之限制所產生的利與不利，皆無損於兼愛的實踐精神。

Mozi’s theory of Jian Ai was reconstructed under the form of western philosophy by many scholars. However, I discover that Mozi used different kinds of argumentations to justify Jian Ai concerning different audience. When facing the opponent, Mozi justified Jian Ai by refuting arguments. And he encouraged supporter’s faith through publicizing the principle of reciprocity. However, the practical spirit of Jian Ai is not elucidated by the principle of refutation and reciprocity. This research tries to figure out the practical spirit of Jian Ai from Mozi. My conclusion is that to practice Jian Ai is the value itself. Regardless of any additional benefit, action of Jian Ai is morality. Moral practice is originated from Jian Ai. Although the realistic benefit is limited by causality the practical spirit of Jian Ai is intact.