Concerning the concept of actus in Thomas Aquinas’ “Summa theologiaе”

The article discusses the main directions of application of the term actus in Thomas Aquinas’ “Summary of Theology”. Firstly, it is presented the prospect of his understanding of theological problem of nature and status of angels in the hierarchy of the Universe. In this context the initial setting of Aquinas’ angelology, which has developed in the course of his many years of reflections and in the frames of a fundamental theological discussion, is demonstrated that an angels do not include in themselves a composition of matter and form, but they have a composition of potency and an act. It is stressed that the form has an independent existence in angels, and they are characterized by a “self-existing form”, hence, they are “separated substances”. As a result, it is concluded that angels, according to the conception of Thomas, are acquired a special disposition in the hierarchy of ens creatum. Secondly, the analyze is developing in the prospect of refuting by Aquinas the heresy of the Manicheans and asserting a kind of “apology” for the existing world. In this sense, Thomas Aquinas’ interpretation of being is considered, which is understood as actuality and perfection, that allows the medieval thinker to demonstrate the unique role of the Creator for the existence of created world. Thirdly, it is presented the horizon of explication of human mind meaning within the framework of the procedure of a moral act. In this regard, the article opens the general scheme of a human act formulated by Thomas and reveals the significance and role of reason and will at each stage of the implementation of moral action, which was a fundamental problem for the ethical studies of his time. Thus, the article is demonstrated the refraction of metaphysical discourse and philosophical terminology, in particular, the concept of actus, dating back to the Aristotelian energia, in the theology of Thomas Aquinas, which allowed him to solve the fundamental intellectual problems of his epoch.