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Reflections on “Systems – the Science of Everything”

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Did you ever get the feeling, when you’re working on some problem (scientific or otherwise), that there are some basic principles at play that elude you, but that must have been worked out already by somebody? That’s certainly been my experience in my career in biology, whether it was in developmental biology, human genetics, neuroscience or other areas. I’ve felt the joy of discovering new components of systems and working out some interactions and pathways, but also a nagging feeling that I was not seeing the whole picture – that I was elucidating details of what was happening, but not grasping what the system was doing . I often felt like I lacked the principled framework to even approach that question. This was not because such frameworks don’t exist but because I had never learned about them – systems principles had simply not been part of my education.   This seems to be true across many disciplines. We’re all so specialised that we have to concentrate on the specifics of our
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How many neurons does it take to change a lightbulb?

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I’ve been reading this excellent paper by David Barack and John Krakauer, on “ Two Views on the Cognitive Brain ”, and it made me wonder about which mode of nervous system function might have come first. To use their terminology, the “Sherringtonian” view (named after Charles Scott Sherrington ) focuses on individual neurons as the elementary units of control, computation, and cognition. In this view, neurons can be thought of as individual relays in a control circuit (such as a reflex) or as elements performing discrete logical operations, which can be combined into larger circuits to carry out more complex computations. It’s all very bottom-up, algorithmic, and mechanistic (and, indeed, provided the inspiration for artificial neuronal networks, as conceived by McCulloch and Pitts ). The “Hopfieldian” view (after John Hopfield ), by contrast, takes the view that more global and dynamic patterns of activity across populations of neurons are the elements encoding and representing cogni
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Getting to the bottom of reductionism – is it all just physics in the end?

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There was some interesting recent discussion on Twitter regarding claims made in a new book by physicist Sabine Hossenfelder , in which she at least seems to assert that everything that happens in the universe is reducible to, and deducible from, the low-level laws of physics. Strikingly, she presents this view as an irrefutable scientific fact, rather than an arguable philosophical position. It’s worth digging into these ideas to probe the notion that the behavior of all complicated things, including living organisms, just comes down to physics in the end.     Patrick Baud quoted several passages from the book, “ Existential Physics ”, that argue that reductionist theories are the only game in town. With the important caveat that I have not read the book in full, and granting that some additional nuance is probably added elsewhere, it is worth quoting these passages in full to try and get the gist of these arguments. I’ve interspersed a few brief comments between the quoted sectio
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