The Christian world needs a revival! It needs to come to a genuine knowledge of God. Not a speculative knowledge, as those retrievers of Aquinas would have it; but a concrete known knowledge of God gifted to us in God’s Self-exegesis in Jesus Christ. When God becomes a predicate of a notional ‘godness’ that ‘we’ (think the philosophers) connive, God 
simply becomes a projection of our own faces (Ludwig Feuerbach knew this well). But this is the God that the evangelical Reformed types these days are introducing people to. Not the God of the Bible revealed in Jesus Christ, but the god of the philosophers, whether that be of Aristotle, Plotinus, or Descartes. The reformational types, if they are going to retrieve anyone, it ought to be a Protestant par excellence, like Luther, rather than the Catholic par excellence, Thomas Aquinas (and the whole mode of philosophical speculation about God that followed).
In the following Eberhard Jüngel offers an insightful comparison between the speculated god of Rene Descartes versus the biblical and concrete God of Martin Luther. As the reader will see, the God of Luther is the kerygmatic God in Jesus Christ.
Remaining at the level of rational knowledge of God, for Luther too there is a fundamental cognitive difference between the “that-being” and “what-being” of God, between the ‘existence’ and the ‘essence’ of God: There is “a vast difference between knowing that there is a God and knowing who or what God is. . . .” Whereas Descartes begins with the ‘essence of God’ which is comprehended in the ‘idea of God’ and moves to the ascertainment of the ‘existence of God’ through the ego . . . , Luther takes another route: “Reason . . . knows that there is a God, but it does not know who or which is the true God. . . .” And it is the misfortune of reason overstepping its boundaries that it wants to move from the knowledge that there is a God somehow to the knowledge of who God is, as Luther says: “Thus reason also plays blindman’s buff with God; it consistently gropes in the dark and misses the mark. It calls that God which is not God and fails to call Him God who really is God. Reason would do neither the one nor the other if it were not conscious of the existence of God or if it really knew who and what God is. Therefore it rushes in clumsily and assigns the name God and ascribes divine honor to its own idea of God. Thus reason never finds the true God, but it finds the devil or its own concept of God ruled by the devil. . . .” For “Nature knows the former [scil. that God exists]—it is inscribed in everybody’s heart; the latter is taught only by the Holy Spirit. . . .” This difference does not obtain for faith. For faith knows that God is in that it experiences who or what God is.[1]
Knowledge of God is, of course!, key to all Christian existence and its theology. Get knowledge of God wrong, and everything subsequent is askew. If knowledge of God isn’t grounded in God’s Self-knowledge given for the world in Jesus Christ, then all that we are left with is a knowledge of God based upon our own whimsical machinations about what godness must be like. If we are left to this mode, the latter iteration, then, in the end, we haven’t been thinking about and talking to the genuine and living God whatsoever; indeed, all that we would have been doing is speaking to ourselves in self-assigned sacrosanct ways. This, I contend, is precisely what the god of Thomism presents the Church with. While this matter is a complex, given intentions and periodization, nonetheless, at an ultimate end what matters is that the Christian gets God right. And the only way to do that is to rely on the God who breaks the philosopher’s god’s back with the weight of His glory as revealed at the cross. Jüngel writes further: “The Cartesian God on the cross—and the cross would collapse! The ‘infinite substance, independent, omniscient, and omnipotent’ is too heavy. And that is its weakness.”[2] Jüngel’s, clearly, is a critique of a Cartesian notional God; I am applying his critique, clearly, to the contemporary Thomists, more broadly. The point of the matter holds true across all philosophers, and their respective notions of godness: they all start with an abstract human reflection about what godness must entail, and then attempt to synthesize the God of the Bible, the God Self-revealed in Jesus Christ, with that. But as Jüngel (and Luther et al.) rightly underscores, this presents us with an irradicable contradiction. The God Self-revealed in Jesus Christ breaks the philosopher’s genius by presenting it with an otherworldly sui generis reality that can only be accounted for by the categories of faith as presented in a logic of Grace.
I hope others will come to grasp the gravitas of these things, and stand against the tide of Thomist and other philosophical retrieval being done in the name of Christ and orthodoxy. There is no orthodoxy ‘but Christ and Him crucified,’ and the logic that the ‘wisdom of the Cross’ is suffused with as if from a new logic that contradicts the old. There is a better constructive way to be an ‘orthodox’ Christian while not selling out to the mainstream of revisionist retrieval being done by most evangelical theologians today; and this, on one hand or the other. Show me someone’s prolegomena, and “what” or “who” their God is will become immediately clear. Let’s be good Protestants, anyway.
[1] Eberhard Jüngel, God as the Mystery of the World: On the Foundation of the Theology of the Crucified One in the Dispute Between Theism and Atheism, trans. by Darrell L. Guder (Eugene, OR: Wipf and Stock [Reprint], 2009), 124 n. 53.
[2] Ibid., 123.