本文著重分析臨床倫理裡的原則主義、決疑論以及現象學方法，且強調了現象學方法的優點。從知識論的觀點看來，原則主義與決疑論以模擬知識論得到的客觀性仍屬於弱化的客觀性，因為它們預設原則與典範（模型）本身即具有客觀普遍性，但對於混雜著不確定的醫學知識與臨床價值衝突時，這樣的客觀性並沒有辦法捕捉臨床的真實情境。本文認為，透過現象學的有效性分析，可以增進臨床工作者更多思考倫理策略與行動的可能性。

This article will analyse three important clinical ethics methods, such as principlism, casuistry and phenomenology, and it will emphasize the advantages of phenomenology. From the view point of epistemology, the objectivities of principlism and casuistry which are gained by simulating epistemology are “weak objectivities”. That is, although they suppose their principles and paradigms (models) have the objective generalities, they can’t catch the clinical situations in reality which is composed of the uncertainties in medical knowledge and the conflicts of moral values. We conclude that it may promote profession in the health care to obtain the possibilities to think about more strategies and activities by practicing the method of phenomenological validity-analysis.