The Catechism of the Catholic Church states this quite well:
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.One of the divine attributes, according to the Dogmatic Constitution on the Catholic Faith from the First Vatican Ecumenical Council, is that, even in His Trinity, God is "completely simple."
Since our knowledge of God is limited, our language about him is equally so. We can name God only by taking creatures as our starting point, and in accordance with our limited human ways of knowing and thinking.
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. 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".
High Cathedral of St. Peter, Cologne, Germany
God transcends all creatures. We must therefore continually purify our language of everything in it that is limited, imagebound 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.
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. 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" (par. 39-43)
The reason truth cannot be reduced, which is why we should not be reductive about truth (i.e., what makes Catholics et/et people) is that truth is in- finite, that is, unbounded. The prefix in is a negative prefix. By contrast "finite" means bounded (the same is true for ae-ternal- the diphthong being a negative prefix). Being reductive is a human attempt to fence truth in. Another way of stating this, which is rooted in the teaching of Msgr. Giussani, is that when we are reductive (this hearkens back to then-Cardinal Bergoglio's short essay in A Generative Thought, especially the short passage about our collective loss of wonder, or transcendence- see Pope Francis moved by Msgr. Giussani) we seek to reduce God and His providence to our measure, which is like insisting you can pour the ocean into a 12-oz glass. As Wittgenstein straightforwardly observed, the only thing that is impossible is a contradiction. As the Archangel Gabriel said to the uncomprehending Virgin Mary after telling her that her heretofore barren cousin, the old woman Elizabeth, had also conceived, "nothing will be impossible for God" (Luke 1:37).
At least for me, this leads into questions about the celebration of the Sacred Liturgy and how it shows all of this time and time again. Pat Archbold wrote (arch)boldly about this last Saturday in "Card. Mahony Tweets On Liturgy. So Do I". Here's one of Archbold's tweets: "humility is about forgetting self, not forgetting beauty." This prompted a few tweets of my own along these same lines: "self-forgetfulness opens us to beauty" and "beauty leads us to self-forgetfulness by striking us with wonder."