For Aquinas for man to make any statement concerning the nature of the Triune God he ipso facto speaks analogously. He is ontologically the Father but he is not a father as defined in human terms. Men predicate things of God’s nature based on his/her own experience of creation; therefore man’s knowledge of God is limited to what he can know of God by analysis of the world – and Scripture of course.
This is why John Calvin said that in order for man to know God he must know himself. We normally cannot know God as Father unless we first know the human role of father (with an implicit knowledge of sonship). Of course God the Father is not merely a duplication of man’s concept of father. He is the archetypal Father. He is the transcendent Father who gives form and meaning to the relationships of mankind.