The metaphysics of morals in Thomas Aquinas: The transcendentals as the foundation for natural law ethics

James Michael Jacobs, Fordham University


This dissertation argues that the transcendentals are the ultimate basis for the precepts of the natural law in the philosophy of Thomas Aquinas. This, in turn, establishes that natural law necessarily relies on metaphysics for its obligatory force. The foundation of all the transcendentals is being, for being, the act of existence, is the necessary intrinsic cause of every entity. The primary characteristic of this transcendental being is that it has the nature of an act and so causes the natural dynamism of all substances in action. From this, Thomas then deduces the other transcendentals as properties which add conceptual notions to being. Among these are the true, by which every creature is intelligible in terms of its act of existence, and the good, the natural inclination of the act of existence to perfection. The discovery of being as the most common property, though, elicits a further metaphysical question about the cause of this act of existence. The extrinsic cause of existence is God, who creates diverse natures as partial participations in the act of existence through the divine ideas. In the divine ideas, each nature is defined according to the end for which it is intended by God; thus, there is a dynamic intention in creation itself. The natural law emerges out of this metaphysics. The first principle of the natural law relies on the recognition of being as the universal ground of existence; with this, we also grasp its dynamic inclination to perfection. Thus, the speculative intellect's grasp of being as the universal cause is extended in the practical intellect's prescription that actions are for the sake of perfection, the good. Therefore, the most general self-evident precept of the natural law is derived by reference to the transcendentals: all beings, qua being, act for the perfection of being. But as this prescription is too general; more specific precepts are necessary. Thus, speculative reason grasps the delimitation of being and practical reason then specifies what is suitable for human nature. These precepts, based on the transcendental properties and the constitutive act of creation, articulate the essence of human ethics.

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Recommended Citation

Jacobs, James Michael, "The metaphysics of morals in Thomas Aquinas: The transcendentals as the foundation for natural law ethics" (2002). ETD Collection for Fordham University. AAI3045128.