Commentary on Catechism of the Catholic Church How Can We Speak about God?

As according to the earlier parts of this commentary (link), it is defensible that we can reason about God, therefore we can speak about God to all men and with all men as well. However, as our knowledge of God is limited, so is our language. Every creature bear a certain resemblance to God, by that reason we can take creatures as the starting point for speaking about God. However, even then we must not confuse the image of God with our human representations and symbols. Our language will always fall short of the true infinitude of God. Regardless, our human language, even if in human representations, do speak about God Himself, though His fullness is inexpressible by His infinite simplicity. It is said that we can only know what God is not and how other beings stand in relation to Him.

Second Commentary

"In defending the ability of human reason to know God, the Church is expressing her confidence in the possibility of speaking about Him to all men and with all men, and therefore of dialogue with other religions, with philosophy and science, as well as with unbelievers and atheists."

There is a necessity of speaking about God to all men and with all men. First of all, evangelization is required to spread the doctrines of God and to make disciples of all men. Second, even with reprobates at least there is a necessity to be the instrumental means of keeping the reprobates at themselves, and keeping them to be at "peace" with the elect. While dialoguing about God with the elect has the instrumental means of their salvation and their increased sanctification. The speech about God is necessarily an improvement for all people, whether it is for the elect or for the reprobates.

"Since our knowledge of God is limited, our language about Him is equally so."

And we will never have a complete knowledge and language of God, as we our fundamentally finite. We can clearly describe God as one word, "God", but that word only communicates the basic understanding of who He is, and not His fullness. Were the word of God alone be sufficient in communicating the entirety of God, we would be obliterated. As only God can comprehend God, no other creature can comprehend God.

"We can name God only by taking creatures as our starting point, and in accordance with our limited human ways of knowing and thinking."

As we have never really seen God, including those who have seen Christ on earth saw His human nature but not His divine nature, which is unseen by those who are still on earth. Therefore we have only seen creatures and so we speak about God by comparing Him to His creatures, that is by what semblance they possess or what greater lack of semblance do they possess. Eventually we must understand that creatures are creatures and God is God, so there is necessity of taking one step higher and higher in speaking about God. Until there is really nothing left to say about God.

"All creatures bear a certain resemblance to God, most especially man, created in the image and likeness of God. The manifold perfections of creatures-their truth, their goodness, their beauty-all reflect the infinite perfection of God."

As all creatures are composed of God and non-existence in some way or another, they will and must reflect God in some way or another. Yet man is created in the image and likeness of God, so they are utmost similar to God, though the angels are arguably more similar to God. However, in the corporeal world, man is indeed the most similar to God. That is why we ascribe various anthropomorphisms to God. Finally man, along with all other creatures, in their variational perfections, reflect the infinite perfection of God, though they are indeed still finite and cannot even amount to any degree of God's perfection. The difference between God and creatures is infinite.

"Consequently we can name God by taking His creatures' perfections as our starting point, for from the greatness and beauty of created things comes a corresponding perception of their Creator."

We can speak about God based on the perfections of the creatures, but they are only a starting point. As I have said before, we must continually elevate our speech to get closer and closer to God. Yet in our natural world and lives, there is a limit to how much we can elevate our speech to God. In our current world, our language has mostly reached its limit, and we cannot express God further without downgrading our language.

"God transcends all creatures. We must therefore continually purify our language of everything in it that is limited, image-bound or imperfect, if we are not to confuse our image of GOd-the inexpressible, the incomprehensible, the invisible, the ungraspable-with our human representations. Our human words always fall short of the mystery of God."

This is what I have said previously, that our language must be elevated continuously as to more accurately express what God is and His true relationship to us. Without that purification we run at risk of confusing the true God and our image or language of God. Such that we may unintentionally commit idolatry by worshipping a mere language or image of God and not God Himself. Our human words can never grasp the depths and heights of God, as He is infinitely deep in Existence and infinitely high at the same time. 

"Admittedly, in speaking about God like this, our language is using human modes of expression; nevertheless it really does attain to God Himself, though unable to express Him in His infinite simplicity."

We are using the analogical method, the method of expressing God in terms of analogy. Therefore,  when we say God is good, we are analogically applying our own goodness to God. God really is good, but His goodness is not the same as our goodness. For in our being, we are composites, we possess this and that, we are made up of this and that. Yet God and His attributes are properly identical such that He is Simple Existence, therefore we can never truly grasp and thus express the true nature of God. We can know it, but we cannot comprehend it, that is to know in totality.

"Likewise, we must recall that between Creator and creature no similitude can be expressed without implying an even greater dissimilitude; and that concerning God, we cannot grasp what He is, but only what He is not, and how other beings stand in relation to Him."

As Creator and creature possess infinite difference, they are analogically similar, but even so there is still a difference of infinity between God and His creatures. Therefore, when we speak or comprehend God in any partiality, we really comprehend His negations and the relationships between Him and creatures. That is why it is said that way in the Catechism.