法律原則真的存在嗎？如果存在，它的地位到底是什麼？是有效的法律？法律的證立理由？或者是法律推理中模糊不明的適用標準？所有這些爭議構成本文的主要關切重當。在本文中，筆者試圖回答以下三個重要爭點：原則是否存在、法律原則是否存在、以及法律原則是不是法律，藉以釐清法律原則的定位及其目的。首先，在詳細檢視Frederick Schauer否定原則存在的論證之後，筆者除了反駁其論點的可取性外，並進一步主張原則具有規約性、普遍性、以及可證立性的定性特徵。其次，筆者批評Larry Alexander與Ken ress的法律原則不存在論，認為其理論一方面無法由法律原則缺乏道德吸引力的規範命題，直接導出法律原則不存在的描述命題，他方面則指出，法律規則與法律原則有不同的規範吸引力，並非由於法律規則具有較明確的行為指引功能，而是因為法律規則的實證性、正規性、以及形式性的外部特徵，使之成為較佳的公共選擇規範。最後，筆者分別探討兩種積極主張法律原則為有效法規範的理論：柔性法實證主義的承認規則理論與Ronald Dworkin的整全法理論，並批判其論點與法律原則的普遍性徵相互矛盾，而難以自圓其說。職是之故，筆者提出消極的法律原則理論，論證法律原則確實存在，且具有一般原則的存在特徵，惟法律原則並非有效的法規範，而是法律上可適用的證立理由，旨在調和法確定性、法保障性、以及法可論爭性的法治價值。

　　　　　Is there any legal principle? If there is, then, what is its status? Is it a valid law, a legal justification, or some ambiguous standard applied in legal reasoning? All these disputes are the main concerns of this article. The author attempts to clarify the status of legal principles by examining three question: "Is there any principle?", "Is there any legal principle?", and "Is legal principle a valid law?" First of all, the present essay closely examines Frederick Schauer's argument against the existence of principles. Not only does the author refute the plausibility of his theory, but also argues that any principle has the defining features of prescriptivity, universality, and justifiability. Secondly, the author rejects Larry Alexander and Ken Kress's theory that defends the non-existence of legal principles. Their argument, on the one hand, unduly derives the descriptive premise that legal principles do not exist from the normative premise that they are not morally attractive. On the other hand, it also fails to establish that the clear guidance of behavior is a distinct virtue of legal rules. The normative attractiveness of legal rules, as I shall argue, is essentially based upon the external features of positivity, canonicality, and formality. All of which make law a better mechanism of public choice. Finally, the author reviews two positive theories that treat legal principles as valid laws. They are the rule of recognition theory defended by soft legal positivism and the law-as integrity theory defended by Ronald Dworkin. Both are inconsistent with the universal feature of principles, however. For this reason, the author proposes the "negative theory of legal principles", which maintains the existence of legal principles but denies their status as valid legal norms. The theory argues that legal principles are legally applicable norms, whose primary purpose is to justify and reconcile three distinctive virtues of the Rule of Law: legal certainty, legal security, and the arguable character of law.