Abstract

Whether the person can understand the essence of God, is thirteen century hotly debated issues. On behalf of the East Greek tradition of Dionysius , emphasizes God's transcendence and unknown, to Augustine and the Western-based tradition, the idea of God in this world there is some kind of knowledge. Thomas Aquinas in his usual way that the old theory of the new advocates were the highest knowledge of God, know God is not; this is a "negative way" , Thomas Aquinas, also known as "separation Road ", to remove people's knowledge, the knowledge of God when the barriers, it can be called a" barrier to the road ". When the Western tradition to understand that God is "own person" when the Greek tradition of ontology, and the integration of Christian theology. St. Thomas Aquinas from the theological framework of human cognitive ability to achieve the conditions and restrictions, and "the road to the barrier" is a rational and accessible by the road of faith, are "mystical theology" , but the method case belongs to metaphysics. This paper describes on the theology of Thomas Aquinas's views, followed by God from the human understanding of the nature of the problem, and discuss "the road to the barrier", and finally the analysis of Thomas Aquinas, "the road to the barrier" of thinking. One of the much debated problems of the thirteenth century, is the question of knowing the essence of God. According to Greek tradition represented by Dionysius the Areopagite, God transcends all things and the best way to know God is the negative way. Augustinian tradition, on the other hand, affirms that human beings have some knowledge of God's essence, even in this world. Thomas Aquinas, in his usual creative synthesis, states that the best knowledge human being can have on earth is to know what God is not. According to him, human being begins by knowing God's existence through the way of causality, then affirming the supremacy of God by way of excellence, and finally by way of negation because God transcends all. The negative way is sometimes called the way of separation or the apopathic way. It is the contention of this paper that when God reveals himself as He Who Is, and Christian thinkers understood it as Being, ancient Greek ontology, Christian philosophy and spirituality become one. Though Aquinas investigates the conditions and limit of human knowledge within the theological framework, the method he uses, is one of metaphysics, and the negative way is the way of Mystical Theology. This paper is divided into three parts: Aquinas's notion of theology; whether it is possible for human being to know the essence of God; nature of the apophatic way