Koons is a reputable philosopher at the University of Texas and, until recently, a life-long Lutheran in the Lutheran Church--Missouri Synod. In announcing his decision to leave Lutheranism and join the Catholic Church, Koons points his readers to a fairly extensive document that reveals his thinking on several doctrinal points.
Cooper's summary is worth reading. In particular, I found several points that resonated with me. Obviously, I came to a different conclusion (for several key reasons) than Dr Koons, but the following issues were the same.
How is it that a teaching so strongly incarnational in principle is so pervasively idealist and nominalist in practice? Just how does Lutheran theology go about describing justification from the point of view of what happens bodily, in this or that person?
Of course, conceptually, it is right, even necessary, to insist on a strict distinction between justification and sanctification. Even Cyril of Alexandria could have said the same about the two natures of Christ—in the abstract! But concretely, is it possible to draw such a hard and fast line? True enough, Lutheran theologians have always admitted that the distinction between faith and works is more logical than temporal. Perhaps Koons overstates the narrowness of the Lutheran position when he represents the confessions as teaching that “no active cooperation by us is involved” in our eventual transformation. Whatever might be said in actual Lutheran preaching, however, the Formula of Concord explicitly asserts a necessary synergy between the regenerate will and the operations of the Holy Spirit. To refuse to cooperate is effectively mortal.
Be that as it may, one cannot help but think Koons is on the mark when he alerts us to the virtual gnosticism in the Lutheran position, at least as it is commonly stated and practiced. Recall Augustine’s famous line: While God created us without us, he doesn’t justify us without us. But it is precisely creatio ex nihilo and Christ’s resurrection from the dead that Lutheranism fastens onto as parallels to God’s act of justifying sinners. I am not denying the fitness of the analogies. After all, they are Pauline (Rom. 4: 17). But once again, what would happen if we tried to read them “bodily” or, as it were, “from below”: Who or what is justified, and to what end?
Similar concerns arise when one considers the insistence in forensic justification on all the real changes taking place coram Deo (before the face of God). Here again, Lutheran teaching is liable to tend toward abstraction. But where else is coram Deo except in the concrete means of grace: baptism, absolution, the sacrament of the altar? Locating our righteousness outside ourselves—in the Christ personally present and active in those means—is fine. Koons observes that epistemologically and phenomenologically speaking, this emphasis is entirely accurate: imputed righteousness “is not introspectible or internally ‘feelable.’” But in order to save, the means of grace must still intersect with real people with real bodies and intellects and wills. Surely it must be admitted that somehow we are involved, unless one approves of a gnostic disdain for the natural, creaturely order.
Koons has some salient points to make on sola scriptura as well. In Lutheran teaching, each individual believer is obliged to attach him- or herself to an orthodox congregation, using Scripture alone as an evaluative norm. But this, says Koons, is “an impossible burden.” In contrast, “on the Roman Catholic view, the individual believer can recognize the true church, not only by examining its doctrines one by one, but also by investigating its historical connection (via a physical and social chain of transmission) to the apostles.” Koons does not want to his readers to escape their individual responsibility. His point is simply that doctrinal fidelity cannot be separated from institutional unity as a mark of catholicity.