孟子、苟子是戰國時代前、後兩位儒家代表人物;兩人在道德學說的心性論層面，一主「性善說」'另一則持「性惡諭」0本文藉由針對孟、苟二家立場有別的心性論觀點， 到底依循怎樣的思維路徑建立，以及兩家之觀點背後，究竟預設何種基本信念等等問題的探討，希望發掘、閻明他們的心性論說，在建構道德哲學上的可能價值和現代意義。透過比論孟、苟兩人的心性學說，以及進探他們各自在天、人關係問題層面觀點的義理連繫之後，本文認為孟、苟兩人對於「天(道)」所抱持的不同信念，一方面導致他們對人性問題表現出似相背反的看法，而另一方面使得他們的道德學說，呈顯出形上學取向與倫理學取向的思維差異。然而，檢視孟子立足在肯定「天道」與「良心」同一所建立的「人性之善」論點，以及苟子基於「人道j與「情欲」異質所指出的「人之性惡」看法，則將發現:前者著重點出了人類的道德自覺能力，而可激起道德實踐的熱望:後者強調說明了禮制、師法的重要，乃能促使世人關注道德價值的客觀化課題。因此，孟子與苟子的心性論說，固然有所不間，但是，剋就建立具有現代意義的道德哲學而言，二家母寧應該相互取法、彼此輔成。

Mencius and Xunzi were two leading figures in Confucianism representative of the earlier and later Warring Periods; of the two's moral doctrines of human nature， one asserted the theory that human nature was good， and the other that human nature was evil. This article attempts to discuss issues concerning how human nature varies from the standpoint of Mencius' teachings and Xunzi's teachings; by what thinking path the teachings were devised; what kind of fundamental belief stands behind the viewpoints of the two teachings and the like in anticipation of exploring their respective human nature reasoning; and what probable value and modern significance the two teachings may have in moral philosophy Upon comparing and profiling the theories of human nature of Mencius and Xunzi， and upon further exploring the linkage in theoretic reasoning of their respective viewpoints in terms of the correlation of divinity versus humanity， this article contends that what sets off Mencius and Xunzi to take to different faiths in the empirical truth， or morality， has been a manifestation of how both held distinctly differing viewpoints towards the issue of human nature. Their distinct moral doctrines further highlighted the differences in their thinking in that one leaned towards a configural orientation and the other towards a moral orientation. Nevertheless， Mencius built his viewpoint around the assertion that human nature was good， recognizing the empirical doctrine and good conscience of the mind， whereas Xunzi built his viewpoint around the assertion that human nature was evil， derived from the differences in humanity doctrine versus human desires. Mencius focused on the human's moral self-awareness capability that would aspire to moral fulfillment， whereas Xunzi emphasized the importance of the etiquette system， law and teaching that served to remind the people of issues concerning car ing for the empirical doctrine and the value of being objective. Although the theories of human nature between Mencius and Xunzi somewhat differ， it would be more rational to mirror the teaching of the two schools in a complementary manner when it comes to mapping the significance of their teachings in moral philosophy.