#7 Kevin Mitchell: Free Agents (in an evolving block universe)

12/05/23 • 80 min

Kevin Mitchell is an Associate Professor of Genetics and Neuroscience at the Trinity College Dublin. He recently published his second book, "Free Agents: How Evolution Gave Us Free Will." It's a rigorous defense for why we (and other living systems) have free will, arguing all the way from quantum indeterminacy, to C. elegans, to how humans can form abstracted meanings over very long timescales. We also go beyond the book, exploring how free will links to unresolved questions in physics about the discrepancy of microscopic laws being time-invariant and macroscopic laws having a time asymmetry (entropy increase over time). And how the 'present' does it exist and how its duration might differ for a fly vs a human. Kevin also does a great job of explaining why top-down causality and meaning are not just some mythical concepts, but how it scientifically makes sense to speak of neural activity in terms of 'what this means for the orgasm', and how coarse-gaining allows hierarchical control structures to do causal work on this 'meaning-level'. In the end, we also talk about what kind of research Kevin would like to see and advice on learning across disciplines.

For Apple Podcast users, find books/papers links at: https://akseliilmanen.wixsite.com/home/post/pod07

Kevin's Website
Twitter: @WiringTheBrain
Kevin's publications & talks:

Mitchell, 2020 - Innate: How the Wiring of Our Brains Shapes Who We Are book
Potter et al., 2022 - Naturalising Agent Causation paper
Mitchell, 2023 - The origins of meaning – from pragmatic control signals to semantic representations preprint
Mitchell, 2023 - Free Agents: How Evolution Gave Us Free Will book
Mitchell et al., 2023 - Robert Sapolsky vs Kevin Mitchell: The Biology of Free Will | Philosophical Trials #15 YouTube
Mitchell, 2023 - Reflections on “Systems – the Science of Everything” Blog

Other papers/books mentioned:

Smolin et al., 2021 - The quantum mechanics of the present preprint

Neuroscience and Philosophy Salon website

My Twitter @akseli_ilmanen
Email: akseli.ilmanen[at]gmail.com
Brain Space Time Podcast, my blog, other stuff
Music: Space News, License: Z62T4V3QWL

Timestamps:

(00:00:00) - Intro

(00:02:40) - The Free Will skeptics

(00:12:56) - Quantum indeterminacy, the weather, and living systems

(00:23:09) - C. elegans and how evolution exploits noise

(00:38:08) - The arrow of time and the quantum mechanics of the present

(00:43:50) - 'How long' is the present for flies vs humans

(00:52:14) - Top-down causality on the biological implementation level

(01:00:03) - Meaning as functional (not epiphenomenal) and Robert Nozick's pleasure machine

(01:05:34) - Interdisciplinary science and education

For Apple Podcast users, find books/papers links at: https://akseliilmanen.wixsite.com/home/post/pod07

Kevin's Website
Twitter: @WiringTheBrain
Kevin's publications & talks:

Mitchell, 2020 - Innate: How the Wiring of Our Brains Shapes Who We Are book
Potter et al., 2022 - Naturalising Agent Causation paper
Mitchell, 2023 - The origins of meaning – from pragmatic control signals to semantic representations preprint
Mitchell, 2023 - Free Agents: How Evolution Gave Us Free Will book
Mitchell et al., 2023 - Robert Sapolsky vs Kevin Mitchell: The Biology of Free Will | Philosophical Trials #15 YouTube
Mitchell, 2023 - Reflections on “Systems – the Science of Everything” Blog

Other papers/books mentioned:

Smolin et al., 2021 - The quantum mechanics of the present preprint

Neuroscience and Philosophy Salon website

My Twitter @akseli_ilmanen
Email: akseli.ilmanen[at]gmail.com
Brain Space Time Podcast, my blog, other stuff
Music: Space News, License: Z62T4V3QWL

Timestamps:

(00:00:00) - Intro

(00:02:40) - The Free Will skeptics

(00:12:56) - Quantum indeterminacy, the weather, and living systems

(00:23:09) - C. elegans and how evolution exploits noise

(00:38:08) - The arrow of time and the quantum mechanics of the present

(00:43:50) - 'How long' is the present for flies vs humans

(00:52:14) - Top-down causality on the biological implementation level

(01:00:03) - Meaning as functional (not epiphenomenal) and Robert Nozick's pleasure machine

(01:05:34) - Interdisciplinary science and education

Previous Episode

#6 Kate Jeffery: Grid cells in 3D, entropy & climate change

Kate Jeffery is the head of the school of psychology & neuroscience at the University of Glasgow (formerly at UCL). This episode is all about grid cells (background info), which Kate was already recording in the 1990s. We discuss how grid cells' rate maps differ when the rats climb in 3D spaces. Here we cover anything from cross-species comparisons (bats, birds), to self-organizing dynamics, and symmetry breaking. Kate also shares her (maybe unpopular) thoughts that the hexagonal grid regularity is not functional but a by-product. We also get physics-y by discussing entropy, evolution, complexity and how they link to memory and the arrow of time. At the end there is career advice and some thoughts on climate change.

For Apple Podcast users, find books/papers links at: https://akseliilmanen.wixsite.com/home/post/pod06

Not familiar with place, grid or head direction cells? Here is my 5min primer.

Kate's Website
Kate's publications:

Jeffery et al., 2015 - Neural encoding of large-scale three-dimensional space—properties and constraints paper
Casali et al., 2019 - Altered neural odometry in the vertical dimension paper
Jeffery et al., 2019 - On the Statistical Mechanics of Life: Schrödinger Revisited paper
Jeffery et al., 2020 - Transitions in Brain Evolution: Space, Time and Entropy paper
Grieves et al., 2021 - Irregular distribution of grid cell firing fields in rats exploring a 3D volumetric space paper
Jeffery, 2022 - Symmetries and asymmetries in the neural encoding of 3D space paper
Rae et al., 2022 - Climate crisis and ecological emergency: Why they concern (neuro)scientists, and what we can do paper

Other reading mentioned:

Cheng, 1986 - A purely geometric module in the rat's spatial representation paper
My article on Michel Foucault and climate change deniers

My Twitter @akseli_ilmanen
Email: akseli.ilmanen[at]gmail.com
The Embodied AI Podcast, my blog, other stuff
Music: Space News, License: Z62T4V3QWL

Timestamps:

(00:00:00) - Intro

(00:02:14) - Missing out on a Nobel Prize

(00:11:05) - Place cells & grid cells interactions

(00:15:19) - Grid cells and rats climbing in 3D

(00:27:24) - (Spatial) ecological niches of rats, bats and birds

(00:32:55) - Self-organizing dynamics

(00:35:36) - 'Speed' in navigating physical vs abstract spaces

(00:40:19) - 3D = 2D planes stitched together?

(00:46:22) - Symmetry breaking in

(00:50:20) - 'A purey geometric module' (Cheng, 1986)

(01:01:24) - Why are grid cells grid-like?

(01:05:22) - Kate's (grid cell) secrets

(01:08:18) - Entropy, evolution, and complexity

(01:17:45) - Memory as metastable states

(01:22:07) - Entropy, memory & the arrow of time

(01:25:03) - Career Advice

(01:28:35) - Climate change & sociology

(01:38:07) - New position in Glasgow

Next Episode

#8 Uri Hasson: Language in the real world for brains and AI

Uri Hasson runs a lab in Princeton, where he investigates the underlying neural basis of natural language acquisition and processing as it unfolds in the real world. As Uri visited Tübingen (where I am doing my master's), we were able to meet in person. Originally, I planned to talk about his idea of temporal receptive windows, and how different brain regions (e.g. default mode network) operate at different timescales. However, we ended up talking more about Wittgenstein, evolution, and ChatGPT. An underlying thread throughout the conversation was that (for both biological and artificial agents), language is not clever symbol and rule manipulation but a brute force fitting to statistics across (Wittgensteinian) 'contexts'. This view is best articulated in Uri's Direct Fit paper. We also connect this to transformers and discuss what's missing in AI. The answer here is multimodal integration, episodic memory, and interactive sociality). At the end, I ask Uri about his 1000 days project, talking to crows, and "understanding" in neuroscience/AI.

For Apple Podcast users, find books/papers links at: https://akseliilmanen.wixsite.com/home/post/pod08

Uri's Website
Twitter: @HassonLab
Uri's publications & talks:

Hasson et al., 2015 - Hierarchical process memory: memory as an integral component of information processing Temporal receptive windows paper
Hasson et al., 2020 - Direct Fit to Nature: An Evolutionary Perspective on Biological and Artificial Neural Networks paper
Yeshurun et al., 2021 - The default mode network: where the idiosyncratic self meets the shared social world paper
Goldstein et al., 2022 - The Temporal Structure of Language Processing in the Human Brain Corresponds to The Layered Hierarchy of Deep Language Models preprint
Nguyen et al., 2022 - Teacher student neural coupling during teaching and learning paper
Goldstein et al., 2022 - Shared computational principles for language processing in humans and deep language models paper