本文將處理荀子的人性理論與天道論觀念，企圖釐清其理論內涵及彼此關係，以及探究荀子性惡論思想成立的可能性，並為儒學在人性論與天道論發展脈絡中一個重要的理論型態作義理定位。文中指出，荀子人性論主張之性惡觀，實是能人性現象的直接觀察所得，作為歸納論證的結論，其實不能成立。並且，荀子主張聖人制禮義以治亂，則聖人制禮義之人性何在？荀子說這就是聖人積漸努力的結果，也是聖人與常人不同的地方，至於聖人之性亦仍與常人相同。然而聖人又如何制禮義呢？這就是依據大清明心，大清明心又只是一理性冷靜的思維知能，亦非價值義的主宰心。那麼聖人之制禮義還會不會有來自天道的意志或普遍原理的依據呢？這就要訴諸荀子特出的天論思維，結果，荀子的天論一致性地同於人性主體的大清明心，依然是一個定常有則的理性秩序而已，亦並非有道德目的性，故而是一自然無目的性的天道觀，天人各司其職，因此荀子的天道觀不能作為聖人制禮義的依據及保證，當然也不會是誰出性惡論的理由，天論與人性論劃分兩橛。就此而官，自然義的天論應該誰出自然義的人性論，但荀子一定要講性惡論，這就顯示他的思路是一重視禮法的心理背景下做出的過於主觀的論斷了。

This paper is to deal with Xun Zi's theory about human nature and ideas about the heavenly way, in attempts to clarify the content of these theories and the relationships in between, explore the possibility of the confirming Xun Zi's doctrine of sinful nature, and establish his theory as an important theoretical doctrine in the development of the doctrines of human nature and heavenly way. In this article, it's pointed that Xun Zi's doctrine of sinful nature is the result of his observation of human nature and shouldn't be regarded as the conclusion of inductive reasoning. Besides, Xun Zi claimed that it's saints that instituted rituals and rites. In that case, where is the saints' human nature of instituting rituals and rites? Xun Zi said that this was exactly the result of the saints' accumulated efforts and what distinguishes saints from ordinary people. As for human nature, the saints and ordinary people are the same in this regard. Then how did the saints institute rituals and rites? They did it through the clear mind, which is a rational and calm thinking rather than a mind to control the value of meaning. Then is the saints’ instituting of rituals and rites founded on the heavenly mandate or any universal principles? To answer this question, we have to resort to Xun Zi's unique thinking about the doctrine of the heaven. As a result, we find that Xun Zi's doctrine of the heaven is totally consistent with the clear mind of human subjects, being a constant order of rationality and therefore a doctrine of the heavenly way without any purpose. Consequently, Xun Zi's view about the heavenly way can be neither the ground nor the guarantee of the saints’ instituting of rituals and rites, and definitely not the cause of his doctrine of sinful nature. His doctrine of the heaven and doctrine of human nature are distinct from each other. A naturalistic doctrine of the heaven is supposed to lead to a naturalistic doctrine about human nature. Since Xun Zi was persistent in his doctrine of sinful nature, we can be assured that his thinking is over subjective, emphasizing totally rites and laws.