There are three questions we have about God just as there are three questions we can ask about anything: What is it? How do we know it? How do we express it or communicate it? One Greek word summarises this, the word means all of these things; intelligent being, intelligent knowing and intelligent communicating. The Greek word “logos”. Logos means  objective order, or intelligible reality; and it can also mean human reason or intelligence or knowledge or wisdom or science. And lastly it means word or language or communication. “Logos is the unity in those three concepts.” (pp 29) The three dimensions of Logos are the same three dimensions of philosophy. Ancient and medieval philosophical ideas focused on the first dimension; the nature of reality, ergo metaphysics. Classical modern philosophy (starting with Descartes) centred on the second dimension, human knowledge; how we know we can be certain, ergo epistemology. Contemporary philosophy targets the last dimension; how words can mean things or even whether words mean anything.

Aquinas organises his Summa around these three things. After proving the existence of God he goes on to state:

“When the existence of a thing has been ascertained, there remains the further question of the manner of its existence, in order that we may know its essence [manner of existence]. Now . . . we cannot know what God is but rather what He is not . . . therefore we must consider, first, how He is not, second, how He is known by us, and third, how He is named.”

This is about the philosophical knowledge of God, knowledge solely by natural reason, not by faith or religious experiences. “Aquinas believes all of these ways of knowing God are valid, but we’re confining ourselves to philosophical knowledge by natural reason here.” (pp29)

There are at least four metaphysical principles that Aquinas uses to show that humans can know God. They are: creation, cosmic hierarchy, the analogy of being and human reason as participating in divine reason.

Creation

“If God created the universe, that establishes a relation between God and the universe, and therefore the possibility of a relation between God and man, and between the Mind of God and the mind of man” (pp 30). Therefore any creation must tell us something about the creator. However, Aquinas does not go into specifics of a deity. As Aquinas states “From effects not proportionate to the cause no perfect knowledge of the cause can be obtained. Yet from every effect the existence of its cause can be clearly demonstrated, and so we can demonstrate the existence of God from His effects even though from them we cannot know God as He is in His essence.” But we can know something about God through the principle of causality, since creation is a causality: to create is to cause the very existence of the effect.

Cosmic Hierarchy

To this point, the notion that God created the universe and is not only divine power, but also divine intelligence, and thus design and order in the universe in implied. This leads Aquinas to state that the universe was created by God in an ordered hierarchy, a cosmic ladder or a “chain of being”. This also stems from his fourth proof for the existence of God; that everything has degrees of perfection.