Davide Weible will defend his doctoral thesis titled „Exaptation: Towards a Semiotic Account of a Biological Phenomenon” on 14 June 2016 at 12.15 (Jakobi 2 - 306).

Summary: The present dissertation attempts a modeling of the evolutionary phenomenon of exaptation according to C. S. Peirce’s theory of signs and inference. To accomplish this, the first section (“Before exaptation: preadaptation and Chauncey Wright”) focuses on the meaning of the concept and reveals its vast historical background. Special attention is paid to C. Wright’s principle of new uses of old powers and his intellectual relationship with Darwin.

The second section (“Wright and Peirce on pragmatism and evolution”) investigates then similarities and differences between Wright and Peirce, especially insofar the epistemological status of Darwin’s theory, their different approach to Lamarck’s account and the issue of evolutionism as a generalization from biology to other fields are concerned. The third section (“Peirce’s evolutionism: the role of continuity and iconic abduction”) further elaborates on evolution and deepens Peirce’s interpretation of Lamarckism by emphasizing his physiological translation of the theory of inference; besides, the role played by perception and similarity is considered central to the working of such framework.

The fourth section (“Abduction and exaptation”) exploits several concepts — substitutability, mistake, categorical perception — to set up properly the modeling: exaptive phenomena can follow sensory-driven changes of behavior, based on similarities among world entities that are interpreted iconically. The fifth section (“The iconic and exaptive logic of technological development”) applies what previously achieved to the issue of technological development and corroborates the idea of cooption as the basic mechanism underlying both abduction and exaptation.

The sixth section (“The origin of bloodsucking: a case of evolutionary abduction?”) is a case study and puts forward the hypothesis that hematophagy might actually have originated through a process integrating abduction and exaptation. The seventh (“Concluding remarks on the case study”) and eight sections (“General conclusions”) explain accordingly specific and general findings of the thesis.