Turing, from the Paradigm of Formal Writing to the Non-Written Emergence of Forms

The article is an introduction to the “Looking back at Turing: His Heritage Today” special issue #72 of the review Intellectica and defends a new interpretation of Turing’s work: far from considering computation in an abstract way without taking into consideration its anthropological conditions of possibility, computation thereby appears as instituting a new stage in the long history of writing. Turing’s intellectual development which thus takes shape is not that of the discovery and application of computation in an undifferentiated way whatever the field of determination but an exploration in three phases going from the formalist notion of computation to the constitution of computer science and the further study of the emergence of biological forms. Hence the three parts of the issue that the introduction describes: computability; cryptology and natural and social dynamics; morphogenesis in theoretical biology. The internal coherence of Turing's development is hence grasped, based on the constantly reworked polarities of the computable and the uncomputable, the predictive and the non-predictive, the logico-arithmetic of the discrete and the geometry of the continuous, the written and the unwritten. It is in the light of these polarities that the influence of Turing is measured today.