As we all know by now Karl Barth was not a proponent of natural theology, or the analogia entis (‘analogy of being’). But what we do find in Barth is an appeal to ‘secular parables,’ something equivalent to what Thomas Torrance, in his own way, calls ‘social co-efficients.’ These Barth parables are grounded in his alternative approach to the ‘analogy of being’ in his analogia fidei or analogy of faith stylized mode of theological endeavor. Kenneth Oakes in his book Karl Barth on Theology&Philosophy helps us gain further insight into how parables functioned in Barth’s thought, particularly as that was operative in Barth’s Der Römerbrief II. Oakes writes:
While notorious for his dialectics, Romans II is one of the most analogical works within Barth’s oeuvre. Romans II belongs alongside CD III/1 and III/2 given prominent and significant role the concept of ‘parable,’ or Gleichnis, plays throughout the commentary. While Spieckermann has noted the presence of an ‘analogy of the cross’ in the commentary and Beintker has pointed out the analogies between divine acting and speaking and human acting and speaking, the full extent of Barth’s use of analogy and the pivotal functions it serves have largely been ignored. In contrast to the analogy of faith he develops in CD I/1, whereby a correspondence exists between God and the subject who knows God, in Romans II Barth talks about parables between the corruptible and the incorruptible, between each ‘moment’ in time and the ‘Moment’ of revelation, between this world and human history and the coming world, between Christ’s resurrection and our resurrection, and even between the No-God of our own making and the one true God. When discussing Romans 8:1–2 with an eye to Christ taking on the likeness (omoiōmati) of sinful flesh (Rom 8:3), Barth notes ‘there remains nothing relative which is not relatedness, nothing concrete which is not a reference to something beyond itself, nothing given which is not also a parable.’ In Christ, God has taken up what is worldly, historical, and ‘natural’ and has re-established its relativity to God. Everything corruptible is indeed a parable, but only a parable, of the incorruptible God, who is still qualitatively different from creation. Neither dialectics nor the infinite qualitative distinction can negate the myriad of analogies that arise from Barth’s use of the concept of parable. The different types of dialectics in the work often serve the same purposes as Barth’s invocation of ‘parable’ in Romans II: to relate and distinguish creation and God, to qualify all statements about God as statements made by fallible humans, and to emphasize the ‘not yet’ of God’s final redemption over the ‘already’ of the salvation wrought by Christ. The infamous ‘infinite qualitative distinction’ does not obliterate the possibility of analogies between God and the world, but provides the infinite difference which provokes and enables the use of analogy in the first place.
It might seem like Barth is playing fast and loose here; it might seem like he is opening the door to natural theology by attempting to find analogies in the creation, analogies that point to God. But remember, as Oakes underscores, these parables are first given context from within Barth’s ‘analogy of faith;’ and these analogies, in the creation, are given telos as they find eschatological reality within the orientation of the new creation realized in the resurrection of Jesus Christ. So for Barth there is no abstract creation or naturum purum (pure nature), there is only what God has created in the first and second Adam by His Triune grace. There is no nature/grace duality in Barth; for Barth, even his doctrine of creation is funded by a strong doctrine of grace, a grace that ‘goes all the way down’ (to quote a Torrancism).
 Kenneth Oakes, Karl Barth on Theology&Philosophy (Oxford/New York: Oxford University Press, 2012), 75.