Let me define some things. By "epistemology" we mean our way of knowing. The cross, in this view, interrupts our previous way of knowing the world, replacing it with a radically different way of knowing. The cross changes how we see the world.
The simplest example of this is Paul's claim in 2 Corinthians 5.16:
From now on, therefore, we regard no one from a human point of view; even though we once knew Christ from a human point of view, we know him no longer in that way.
One way of knowing Christ -- from "a human point of view" -- has been replaced with a radically different point of view. An epistemological change has occurred. Because of the cross, we now see the world differently.
From this new perspective, different valuations follow. We have radically new metrics of value. From "a human point of view" something might be shamed and despised. But from our new epistemological perspective, these shameful things are actually honored and valued. The same goes for the honorable and glorious things in the world. From "a human point of view" something might be valued by the world. But from the point of view of the cross, these glorious things are actually deemed to be worthless, even as trash and waste. You see this re-valuation of values in 1 Corinthians 1:
For the word of the cross is folly to those who are perishing, but to us who are being saved it is the power of God. For it is written,
“I will destroy the wisdom of the wise, and the discernment of the discerning I will thwart.”
Where is the one who is wise? Where is the scribe? Where is the debater of this age? Has not God made foolish the wisdom of the world? For since, in the wisdom of God, the world did not know God through wisdom, it pleased God through the folly of what we preach to save those who believe. For Jews demand signs and Greeks seek wisdom, but we preach Christ crucified, a stumbling block to Jews and folly to Gentiles, but to those who are called, both Jews and Greeks, Christ the power of God and the wisdom of God. For the foolishness of God is wiser than men, and the weakness of God is stronger than men.
For consider your calling, brothers and sisters: not many of you were wise according to worldly standards, not many were powerful, not many were of noble birth. But God chose what is foolish in the world to shame the wise; God chose what is weak in the world to shame the strong; God chose what is low and despised in the world, even things that are not, to bring to nothing things that are, so that no human being might boast in the presence of God.
The preaching of "Christ crucified" creates an epistemological crisis which leads to different modes of valuation. Things intellectually valued by the world are now viewed as foolish. Things viewed as strong by the world are now viewed as weak. Things honored by the world are now viewed as shameful. Conversely, in light of Christ crucified, things the world deems foolish, weak, and shameful are viewed as wise, strong, and honorable. The cross flips our way of seeing the world on its head.
So, this is what the scholars mean by "the epistemological crisis of the cross." In light of the crucified Christ, our way of seeing the world, our way of knowing and valuing the world, has undergone a seismic change and radical inversion. We no longer regard anything or anyone from a human point of view. To be a Christian, therefore, is coming to see the world in this radically different way.
