Maxwell Ramstead, McGill University
The active inference framework explains a deeply puzzling characteristic of living systems, that they resist the natural tendency towards dissipation; namely, the entropic decay that is dictated by the second law of thermodynamics. Living systems manage to maintain themselves in a limited number of states, i.e., their phenotypical states. How do organisms accomplish this incredible feat? What does it mean to be alive? How are they integrated across the scales at which they exist — from subcellular processes and neural networks, to embodied action and culture? In the active inference framework, the actions and bodies of organisms encode expectations (or Bayesian beliefs) about the world, and act to make those expectations come true.
In this presentation, we will examine the central mathematical construct behind active inference: the Markov blanket. The Markov blanket formalism answers questions usually left to philosophers: namely, What counts as a system? and What does it mean to exist at all? The answer provided by Markov blankets is surprisingly simple, but has profound implications.
A Markov blanket is a set of states that separates a given system from the outside world, in a statistical sense. Markov blankets can themselves be made of Markov blankets, producing a recursively nested structure of “blankets of blankets,” all the way up, and all the way down — and providing an integrative model of cognition and interaction across scales. Our multiscale formulation of active inference allows us to study the adaptive behaviour of dynamical systems of systems, from neural mechanics to cultural niche construction.
Biography: I passed my oral doctoral defence at McGill University (Montreal, Canada) on June 18, 2019. I am affiliated with the Jewish General Hospital in Montreal (as the Douglas Utting Postdoctoral Fellow, starting officially in the Fall 2019), the Division of Social and Transcultural Psychiatry at McGill, and the Wellcome Trust Centre for Neuroimaging of University College London.
I have completed my B.A. in Philosophy at Université de Montréal, my M.A. in Philosophy (specialized in Cognitive Science) at Université du Québec à Montréal, and my Ph.D. in Philosophy at McGill. My research explores social-cultural and computational approaches to depression, as well active inference and multiscale explanation in psychiatry, cognitive sciences, and computational neurosciences. I am grateful that my Ph.D. research project, entitled Have We Lost Our Minds?, was supported by the Healthy Brains for Healthy Lives initiative at McGill and the Social Sciences and Humanities Research Council of Canada
Postdoctoral mentors: Laurence Kirmayer (McGill University) and Karl Friston (University College London)