The Scriptures speak of God as immortal (1 Tim. 1:17), invisible (Col. 1:15) infinite (Psalm 147:5), and so forth. These are apophatic, or negative, predications. ... In reality, we know nothing about what it is to be infinite, invisible (i.e., not merely unseen, but unseeable), or immortal. We do, however, know what it is to be finite, visible, and mortal... [Charles J. Rennie, "Analogy and the Doctrine of Divine Impassibility," in Ronald S. Baines and Richard C. Barcellos et al, eds., Confessing the Impassible God: The Biblical, Classical, and Confessional Doctrine of Divine Impassibility (Palmdale, CA: RBAP, 2015), 75]
God is infinitely beyond us, the Creator transcending everything in creation. We can only know God through His revelation, and the three ways of knowing God are through causation (via causalitis), through negation (via negationis) and eminence (via eminentiae). All this is basic orthodox Christian theism. Concerning the way of negation (via negationis), we know God through a contrast with what He is not. Thus, God is infinite, as opposed to finitude. He is invisible, as opposed to being visible, and so on. But it is one thing to hold to negation as the manner of how we know more about God, and it is another thing to think that the way of negation implies negation of knowledge so that we "know nothing" about what God is concerning those attributes revealed through the via negationis.
It seems to be some weird twisted sense of false humility, but it seems some classical theists prefer to contradict themselves as an exercise in false piety, as if irrationality pleases God. When they say that God is invisible for example, it is a positive declaration of something, i.e. God is not visible. How can it be said that we "know nothing about what it is," as if we cannot picture the negation of something we understand from the natural world? It is true that we cannot comprehend it fully, but to state as if we cannot apprehend something about it is false piety.
Let's just take as an example the attribute of invisibility. Why is that so hard for a modern person to grasp? Rennie did make a distinction between "unseen" and "unseeable," but that has no bearing on whether we can perceive something as invisible, since for most of us, most of the unseen realm is really invisible. Most of us don't walk around with X-ray scanners, or personal sonars when we swim in the ocean, so we can grasp the notion of the unseen. Something that is invisible in the classical sense can be understood as something that extends the range of non-perception beyond the capability of all known detection devices, something like (but certainly beyond) the postulated "gravitons" that are the particles associated with gravity and of which we have not been able to detect.
Even apart from scientific analogies, many things are truly invisible. A man's thoughts are invisible. The laws of physics are invisible. Certainly, God's invisibility is of a different kind from all these, but still it is wrong to say that we cannot apprehend something about what invisibility is.
Similar arguments can be made for almost any attribute known through the way of negation. Again, the point is not whether those attributes possessed by God is qualitatively in a class of its own, which they are. Rather, the point is that just because the way of negation is used does not imply that we "know nothing about what it is like" to have any of these attributes.
It is well and right to be circumspect in dealing with the lofty things of God. We should tremble when dealing with such sacred truths. But we ought not to think ourselves holier than God, and think intellectual self-flagellation pleases God. God reveals Himself in order for us to know Him, not in order for us to turn His truths into unknowing.