In light of the last post my wife and I have been having a discussion regarding the analogy of being. Here is my position in outline.
First, let's define the analogy of being. The analogy of being presupposes that there is a similarity between God and his creatures. God of course does not exist as his creatures exist. He is infinite, eternal, and non-contingent. Nevertheless, he can be said to exist, as can his creatures even if there existence is profoundly different. Hence there is an analogy of being existing between them. Moreover, God's attributes (wisdom, power, goodness, etc.)though infinite and eternal, can be observed as existing in analogous manner in creatures who also possess them. There is a similarity with a still greater dissimilarity between God's reality and his creatures. Such a claim about God allowed the Medieval theologians (particularly Thomists) to claim that their doctrinal statements about God's nature were realistically true, while at the same time allowing for divine mystery.
My difficulty, which I expressed in the last post, is that to my thinking that this amounts to a theology of glory. In other words, the knowledge of God is a matter is seeing past created thing and into God's eternal being. This allows creatures to "see" God (for ancient philosophy the act of cognition is identified with seeing and not with hearing) and thereby attempt to correspond to God's glory. For Thomas in particular, the human creature is supposed to see God's being and thereby gradually become similar to it by the power of grace.
My alternative is not to talk about creatures as analogues for God, but as divine "masks" in accordance with Luther. This is not a Barthian rejection of natural theology, but a revisioning of natural theology by Luther in terms of divine presence and action, rather than ontological likeness and distance.
Luther often speaks in terms that sound (without actually meaning to be) pantheistic or panentheistic. For example, Luther talks about how God channels his goodness to his creatures through created means. When the "fool eats bread, he does not realize that he is eating God in the bread." Luther says that God "wraps himself up" in his creatures. The point here is not that God somehow is identical with the substance of the bread, but rather that God's goodness is active and present through the bread. The bread (or any other creatures) is a mask of God's presence and action. The created entity is a medium of God's goodness in that God can be recognized as creating, sustaining, and acting through the bread to give his goodness to his creatures. It is not analogical of God's goodness because there is no distance of "likeness and unlikeness" between God's creative and sustaining action and its manifestation in the creature. God's graciousness is literally and concretely manifest in that he gives the good through the bread, not a similitude to the good. Moreover, since one only comes into contact with the good that God is giving in, under, and with the creature, it is is impossible to strip away the creature to get to God's naked goodness inside. Hence, the creaturely mask is not as an "image" or analogue for God's goodness. It does not bid us to draw our minds away from the created medium to God "above" the medium (which is the point of analogy), but rather God's actual presence in the bread. I take this to be what Paul means in Romans 1 when he states that God's power and glory are known "in that which was made" (ESV). We can say this with regard to God's activity in creation as we do with regard to redemption. For example, we do not say that the Lord's Supper "reflects" God's willingness to forgive or the presence of Christ, but rather it is these things. In a similar manner, in the OT, the covenant was circumcision.
This is all very consistently with Lutheranism's insistence that the "finite is capable of the infinite." As Gustaf Wingren points out, God's creatures are not alien to him in that made them precisely for the purpose of acting through them. Analogy supposes that the finite can only "reflect" or "echo" the infinite by similitude. For Lutherans, the infinite God can be known truly and directly through the created medium in that it is capable of serving as a vehicle of his infinity. This also corresponds to how Lutherans understand the Incarnation. For Lutherans, the man Christ is the presence of God, whereas for the Reformed and Catholics Christ's humanity reflects God. Denying the genus majestaticum, both Reformed and Catholics talk about the "creatured gifts" (i.e. created analogues of God's divinity in Jesus' humanity) given to the man Jesus.
For this reason, our language about God should be characterized as "sacramental" and not analogical. God cannot, as Luther states, be spoken of apart from the masks of his creaturely coverings. Whenever we speak about God, we are speaking about his presence and activity wrapped in his creatures, not his eternal and hidden being. This is why the analogy as a theological method ultimately does not work. It ignores the means through which God has made himself present to us and seeks to look into his hidden being through the creaturely medium as if they were transparent.