此文係針對永續發展（環保政策之領綱）和定然律令（康德享名之道德原則）之檢視。永續發展在廿一世紀已儼然脫穎而出成為環保政策的全球指標。姑不論其重要性，此環保政策原則尚浮遊於準則性的空泛中。永續發展是為追求人類褔祉、後代子孫的權益和施予自然尊重的行動指導法則。我主張此道德衝力在康德的論說中有其最為完善的分析。我亦將闡明永續發展之模式反映出經由定然律令所表明之道德典範，又此定然律令的三種程式提供了永續發展所欠缺之依據。結合永續發展和定然律令的法則建議了一種對康德原理實際的取讀。這取讀是為定然律令之必然修正－少了它，康德原則便難免於異評。

This paper is an examination of sustainable development and the categorical imperative. Sustainable development has emerged as the global guideline of environmental policy in the twenty-first century. Despite its importance, this policy floats in a normative void. Sustainable development is a rule guiding action aimed at human wellbeing, rights of future generations, and respect for nature. I argue that the ethical thrust of this policy is best analyzed in Kantian terms. I shall show that the pattern of sustainable development mirrors the pattern expressed by the categorical imperative, and that the categorical imperative, in its three formulations, supplies the foundation of sustainable development. Connecting sustainable development to the categorical imperative, however, suggests a pragmatic reading of Kant's principle. This reading is a necessary correction of the categorical imperative--without it, Kant's principle could not be saved from objections.