Nihat Ay
Hamburg University of Technology; external professor, Santa Fe Institute; honorary professor, Leipzig University
Integrated information Consciousness is intrinsic causal power, measured as integrated information
Nihat Ay heads the Institute for Data Science Foundations at Hamburg University of Technology, a position he took in 2021 after sixteen years as a Max Planck Research Group Leader at the Max Planck Institute for Mathematics in the Sciences in Leipzig, where he led the Information Theory of Cognitive Systems group. He is also an external professor of the Santa Fe Institute, an external faculty member of the Complexity Science Hub in Vienna, an honorary professor for information geometry at Leipzig University, and Editor-in-Chief of the Springer journal Information Geometry. His textbook “Information Geometry,” coauthored with Jürgen Jost, Hông Vân Lê, and Lorenz Schwachhöfer, is a standard reference in the field.
Ay’s research connects three things that do not obviously belong together: the differential geometry of probability distributions, the causal structure of networks, and the complexity of learning systems. That combination is what makes his group’s line of work on integrated information possible. With Carlotta Langer, he developed a version of integrated information built from conditional mutual information between the parts of a system, tractable enough to compute on the racetrack-navigating agents in the group’s 2026 paper linking free energy minimization to integrated information.
Ay’s position in the debate is a mathematician’s position rather than a philosopher’s. He does not argue for or against IIT as a theory of consciousness. He builds the calculational machinery that lets IIT’s central claims be tested against other frameworks, in this case Karl Friston’s active inference, and reports what the numbers show.
Known for. Information geometry and information-theoretic measures of complexity and causal integration
Coverage on this site
Related researchers
- Carlotta LangerMax Planck Institute of Molecular Cell Biology and Genetics, Dresden; Center for Systems Biology DresdenMeasures of integrated information for embodied and active inference agents
- Jesse van OostrumHamburg University of TechnologyMathematical formalization of active inference in discrete time
- Karl FristonUniversity College London. Chief Scientist, VERSES AIThe free energy principle and active inference
- Larissa AlbantakisUniversity of Wisconsin-Madison, Center for Sleep and ConsciousnessIntegrated Information Theory 4.0 and dissociating intelligence from consciousness in artificial systems
- Costas AnastassiouAllen InstituteEphaptic coupling of cortical neurons, endogenous electric fields as causal participants in neural activity, extracellular field biophysics
- Anton ArkhipovAllen Institute for Brain ScienceLarge-scale neural simulation, biophysically detailed cortical models, AIBRAIN program, State of Brain Emulation Report 2025
Nihat Ay is listed with the other integrated information theorists, who hold that consciousness is intrinsic causal power, measured as integrated information. The theory family behind that position is set out in the index of consciousness theories. Every researcher covered on this site is indexed in the directory of consciousness researchers.