Like the notion of tension, that of ‘complementarity’ is deceptively simple: it is just as unquestioningly embraced in some contexts as it is rejected in others. The divergent attitudes towards complementarity have much to do with different ways in which this notion conjures up the figure of a whole and specifies the relationship between parts.

‘Our positions are complementary, not in conflict!’ – Recognizing complementarity offers an attractive model for the coexistence of different types of knowledge, systems, and cultures. However, complementarity does not preclude conflict. Also relations of power and resistance, domination and submission, action and reaction, for instance, can be considered as complementary. Furthermore, while a whole may contain parts held together by harmonious tensions between each other and the whole, different positions rarely simply add up like pieces in a puzzle to provide a full, harmonizing picture. The pieces usually seem to be too large and it requires violence to make them fit – for instance, by constructing others as a complement that provides just what one misses – or to make them compatible where they overlap.

At the same time, there are also more specific and peculiar notions of complementarity that do not subordinate parts to a whole or to each other, such as the principle of complementarity that Niels Bohr introduced in order to address the apparent particle-wave duality in quantum physics. Not visualizable in terms of a jigsaw puzzle, this principle remains rather puzzling. It allows for the possibility that different perspectives not only construct objects differently, but also constitute different objects. There seems to be no perspective from which the different parts can be seen together and while Bohr was arguably inspired by multistable figures such as the Rubin vase, he repeatedly emphasized the necessity of renouncing desires for visualization. The pieces of evidence obtained by different, mutually exclusive means appear contradictory when an attempt is made to combine them into a single picture and yet they are equally necessary for a fuller account. Bohr even claims that the quantum-mechanical description of physical reality is complete in order to ward off regressive desires for visualizing the whole. Although the parts and the whole are no doubt related, it is as if the whole had no definite parts and the parts were epistemologically independent, determinable neither by the unrepresentable whole nor by each other.

Such a notion of complementarity unsettles traditional oppositions of subject and object, epistemology and ontology, identity and difference. In particular, it provides a model that complicates part-whole relationships and helps re-think them in ways that promise to be productive also in other fields, such as those of the social, political, aesthetic or biological. For instance, we could ask to what extent the way in which quantum mechanics renounces visualization of the whole while maintaining completeness of description can offer a model for resisting totalizing desires without either mystifying the whole in its unrepresentability or dismissing totality and thereby reifying the particular. Furthermore, in many fields the apparent contradiction between descriptions that cannot be integrated into a representable whole may be taken as a sign that the whole is traversed by an inner difference, tension, contradiction, or antagonism that is replicated both within each part and in the relation between parts. If in this case focussing only on one part and disregarding complementary ones both contributes to the whole’s inner conflict and fails to address it, to what extent would complementarity allow for a more effective strategy for intervention and transformation? Alternatively, to what extent can it provide a way to reconsider postmodern/poststructuralist critiques of totalization at a time when in many domains pluralization seems as repudiated as it was embraced before?

With the focus for 2012-13, the ICI Berlin seeks to inquire about the potential and limits of complementarity for reconsidering questions of totality, the whole and the relation of parts within different fields and to explore further how diverse cultures and discourses can be brought into productive confrontation beyond indifferent coexistence and violent conflict.

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