Background metaphorics - background of images that makes it possible to reconstruct and understand seemingly non-metaphorical (and even purely theoretical) statements.
The language of imaginative horizons here is reminiscent of Heidegger and Gadamer.
62-63: "Metaphorics can also be in play where exclusively terminological propositions appear, but where these cannot be understood in their higher-order semantic unity without taking into account the guiding idea from which they are induced and 'read off'. Statements referring to data of observation presuppose that what is intended can, in each case, be brought to mind only within the parameters of a descriptive typology: the reports that will one day be transmitted to us by the first voyagers to the moon may well require us to engage in a more thorough study of American or Russian geography if we are to grasp the selective typicality of these reports, corresponding to the eyewitnesses' (anticipated) background. Faced with an artificial structure of speculative statements, the interpretation will only 'dawn' on us once we have succeeded in entering into the author's imaginative horizon and reconstructing his 'translation'. What preserves genuine thinkers from the crabbed scholasticism of their imitators and successors is that they keep their 'systems' in vital orientation, whereas academic routine uproots concepts and suspends them in idiosyncratic atomism. In undertaking an interpretive reconstruction, we will succeed in reviving such translations, which we propose to call 'background metaphorics', only within the parameters of a certain typology, and this is most likely to occur where a prior decision between opposed types of metaphors -- between organic and mechanical guiding ideas, for example -- has been made. It is not just language that thinks ahead of us and 'backs us up', as it were, in our view of the world; we are determined even more compellingly by the supply of images available for selection and the images we select, which 'channel' what can offer itself for experience in the first place."
Blumenberg argues that the contrast between mechanical and organic metaphors is itself not fixed, but emerges in the post-classical world. The classical machina has a broader meaning than the modern machine, referring to all sorts of contrivances and tricks. Lucretius' machina mundi does not yet have the connotation of automatism that would come with later clockwork metaphors, it merely contrasts the world as contrived or artful in contrast to the Stoic metaphysics of providence. The distinctive use of machine as a concept opposed organism arrives with the French Enlightenment. Blumenberg thinks that this emergence is more than coincidental, given how it serves the materialistic program of Enlightenment thought. (63-64)
For Plato, the universe was both constructed and living. It had to be conceived of as alive because it was understood to move itself, and ability to move oneself was the criterion of life. Mechanical models, like Archimedes' sphere, were seen by classical authors like as inferior imitations which merely demonstrated the rationality which must exist to a superior degree in the original. In Lactantius we see a Christian recasting of the interpretive function of Archimedes sphere: now it shows that the universe can be in motion after an initial impetus without requiring any animation. There is a clear theological interest behind this: reducing the world to a mere mechanism leaves God alone in transcendence. (64-66)
Nicolaus of Cusa characteristically saw Archimedes' model as a projection of the human mind, an invention created in place of divine creativity rather than an imitation of the universe. While an Aristotelian view of technology as mimetic lent itself to organic metaphors, Cusanus' opens a way to distinctively mechanical metaphors. (67)
Descartes abjures the project of understanding what the world or organisms are in themselves. Instead, he proposes to understand them externally, by transferring our knowledge of mechanical devices as hypothetical stand-ins. Having made the metaphorical substitution of machine for world or organism, however, Descartes is also able to substitute a pragmatic view of the aims of inquiry for a theoretical one: since there is a surplus of possible mechanical constructions which could be made to stand in for any natural entity, the choice between them is made on the ground of what works best (and if the model works better than its natural counterpart, then it a truer example of the original function than what is in nature). (68-70)
Blumenberg contrasts the book of nature and clockwork universe metaphors. The output of the clock -- the actual display of time -- is not significant in the use of the metaphor; what matters is its predictable functioning. For the book of nature, on the other hand, the informative content is critical; what is significant in the metaphor is that there is a message that could be communicated. (71)
The clockwork metaphor emphasizes God's initial creative act at the expense of God's continuing involvement in the world. (71-72)
With the book of nature, man remains external to the metaphor, as the intended reader. Human beings are among the things brought under the clock metaphor, however, in the works of Voltaire and Vauvenargues. The French moralists typically indentified the passions with the internal working of the clock, and reason as the display (in a way that hoped to gain assent and accomplish their aims) of those hidden instincts and passions. (72-73)
In The Crisis of the European Sciences, Husserl metaphorizes the scientific enterprise itself as a mechanism, and metaphorizes the implicit goal of the enterprise as an ideal textbook which puts together all of its achievements in a coherent whole. (75-76)