6 ms·

Space is a latent sequence: A theory of the hippocampus

162 points by XzetaU8 2y ago

smokel 2y ago
[flagged]
- protonfish 2y ago
  The paper is specifically about how space is represented in the human brain. Data representing space can be encoded in many different, but functionally equivalent, ways. Showing how it could be encoded by neurons in the hippocampus is valuable to understand our brain, but philosophically not significant.
  - ithkuil 2y ago
    How can understanding how the world works not be philosophically significant? How did we come to the point where we relegated philosophy to be the study of only the things not connected with reality? I'm fine with thinking about philosophy as a field that also explores ideas that are not connected with reality, but it's not only about those things.
    - meroes 2y ago
      They got sick of philosophers asking tough questions probably.
    - mbivert 2y ago
      > How did we come to the point where we relegated philosophy to be the study of only the things not connected with reality? If it deals with reality, then it's in the realm of science; science being the superior form to tackle such things, there's simply no reasons to involve "philosophy". The only room left for philosophy is thus wherever science doesn't operate. Not that I think it's a good thing: the dogmatic, rigid, mindset advocated by contemporary institutionalized science feels detrimental to a "lighter" approach to life: it's as if people don't have the right to ponder about existence on their own anymore; it's child's play if it's not done in such and such a way.
      - ithkuil 2y ago
        A lot of good science can be done without much philosophy. But you can't have good philosophy if you intentionally avoid science. I regained respect in philosophy by reading the work of philosophers like Dan Dennet who break that unfortunate cliché where philosophy has been stuck to only ponder at the left-overs of science and instead embrace science and apply sound philosophical thinking to navigate the consequences of what we discovered about reality.
        mbivert 2y ago
        > A lot of good science can be done without much philosophy. > But you can't have good philosophy if you intentionally avoid science. As always, it all depends on the definition of "philosophy" and "science". If it's the "love of wisdom" and "knowledge" respectively, then I doubt hardly anything of value can be produced without both philosophy and science; and philosophy should be of greater value (e.g. Socrates' "I know that I know nothing").
- 0xTJ 2y ago
  Philosophy isn't relevant here, this is talking about science and theorizing about the function of real structures in our brains.
  - nonrandomstring 2y ago
    piffle
  - delichon 2y ago
    That statement is a theory of empirical philosophy.
- exe34 2y ago
  So like Narnia looking out of the cupboard?
- delichon 2y ago
  Sucks that this fascinating question is getting downvoted. It seems natural to wonder what the "real" world looks like, given that we see it through such a convoluted set of lenses. Does our sense of time and motion emerge through this latent sequence alone, or are they properties of any kind of memory? Are emotions part of this peculiar path of evolution or a part of sentience? Is sentience dependent on latent sequences?
  - smokel 2y ago
    Thank you for your support. I probably shouldn't have mentioned God, and I guess my remark was a little bit too concise. I'm not too familiar with contemporary philosophy, but recent insights brought on by LLMs sure made me want to revisit Wittgenstein. To take it even further (and risk a few more downvotes? :), are we entering a time where idealism can get a new foundation? It has always seemed pretty suspicious that science is so good at explaining natural phenomena [1]. Combine that with the idea that our brains cannot do more than basic logic [2], and one could easily conclude that we get to see only a very small part of totality. [1] https://en.wikipedia.org/wiki/The_Unreasonable_Effectiveness_of_Mathematics_in_the_Natural_Sciences https://en.wikipedia.org/wiki/The_Unreasonable_Effectiveness... [2] https://en.wikipedia.org/wiki/Church%E2%80%93Turing_thesis https://en.wikipedia.org/wiki/Church%E2%80%93Turing_thesis
fredgrott 2y ago
If you read Wolfram's work you see him talking about this several times...
observationist 2y ago
This is coming from Dileep George and the Jeff Hawkins adjacent theories around hierarchical temporal memory, cortical columns, and much of the higher level theory around what it is that the brain is doing in its smallest, repeated functional units. They split some time back, but they're both quite rigorous and have done exciting research. This paper goes over allocentric framing of learning, allowing cortical networks to be built through learning and thinking over time, driving a more complex and nuanced model of the world to be built throughout the networks in the brain, where the hippocampus seems to hold the long term memory, with connections that feed back up to nearly every region in the cortex. It's not complete, but it abstracts a level away from phenomenological observations like the notion of Jennifer Aniston cells, or mirror neurons, or things that occur as a consequence of some underlying functionality. We're getting much closer to a complete picture of the algorithms underlying human intelligence, and those may unlock human level machine intelligence, the understanding of consciousness, and all sorts of great medicine and technology. Google made a good choice in hiring Dileep George.
- K0SM0S 2y ago
  Agreed. Anecdotal (but deep) research led me to postulate that our entire "inner world", for lack of a better word, is an emergent construction based on a fundamentally spatiotemporal encoding of the external world. This assumes that feeding and motility, i.e., a geometric interpretation of the external world, is among the first 'functions' of living organisms in the evolutionary order. They subsequently became foundational for neuronal systems when these appeared about 500 million years ago. The hypothesis was informed by language notably, where most things are defined in spatial terms and concepts (temporal too, though more rarely), as if physical experiences of the world were the building blocks of thinking, really. A "high" council, a "sub" culture, a "cover", an "adjacent" concept, a "bigger" love, a "convoluted" or "twisted" idea, etc. Representations in one's inner world are all about shape, position, and movement of things in some abstract space of sorts. This is exactly how I'd use a 4D modeling engine to express a more 'Turing-complete' language, a more comprehensive experience (beyond movement: senses, intuitions, emotions, thoughts, beliefs…): use its base elements as a generator set to express more complex objects through composition in larger and/or higher-dim space. Could nature, Evolution, have done just that? Iteratively as it conferred survival advantages to these genes? What would that look like for each layer of development of neuronal—and later centralized "brain"—systems? Think as in geometric algebra, maybe; e.g., think how the metric of a Clifford algebra may simply express valence or modality, for those neuronal patterns to trigger the proper neurotransmitters. In biological brains, we've already observed neural graphs up to 11 dimensions (with a bimodal distribution peak around ~2.5D and ~3.8D iirc… Interestingly for sure, right within the spatiotemporal ballpark, seeing as we experience the spatial world in 2.5D more than 3, unlike fishes or birds). Jeff Hawkins indeed strongly shaped my curiosity, notably in "A Thousand Brains" and subsequent interviews. The paper here immediately struck me as very salient to that part of my philosophical and ML research—so kinda not too surprised there's history there. And I'm really going off on a tangent here, but I'm pretty sure the "tokenization problem" (as expressed by e.g. Karpathy) may eventually be better solved using a spatiotemporal characterization of the world. Possibly much closer to real-life language in biological brains, for the above reasons. Video pretraining of truly multimodal models may constitute a breakthrough in that regard, perhaps to synthesize or identify the "ideal" text divisions, a better generator set for (any) language.
oliyoung 2y ago
First thing that came to mind was the song-lines of Indigenous Australians, they code long journeys through country through narratives and songs, it's the macro form of this research https://en.wikipedia.org/wiki/Songline https://en.wikipedia.org/wiki/Songline
kovezd 2y ago
I've had the theory that our identity begins as an extension of the representation of space. We are simply the node at the center in a coordinate system, connected to the same emotions, rewards, and memories that every other node in the graph.
- HarHarVeryFunny 2y ago
  Pretty sure our identify is just that of the actor behind our own actions. i.e. Our brain models causal relationships, sees the correlation between it's own pre-action thoughts and the following action, and therefore models itself as an actor/causal agent responsible for these thoughts and actions.
  - borbulon 2y ago
    Thank you for this, it’s stirred up a considerable amount of thought in me, but I would also say that my immediate reaction is that > its own pre-action thoughts and the following action Can also be a sort of spatial processing
marmaduke 2y ago
> CSCGs build on top of cloned HMMs by augmenting the model with the actions of an agent. pretty interesting take, and reminds me of the models that Karl Friston and many colleagues make under the umbrella term "active inference", involving free energy minimization.
altairprime 2y ago
If you read nothing else in this paper, read the first two diagrams.

162 points by XzetaU8 2y ago

smokel 2y ago

[flagged]

protonfish 2y ago
The paper is specifically about how space is represented in the human brain. Data representing space can be encoded in many different, but functionally equivalent, ways. Showing how it could be encoded by neurons in the hippocampus is valuable to understand our brain, but philosophically not significant.
- ithkuil 2y ago
  How can understanding how the world works not be philosophically significant? How did we come to the point where we relegated philosophy to be the study of only the things not connected with reality? I'm fine with thinking about philosophy as a field that also explores ideas that are not connected with reality, but it's not only about those things.
  - meroes 2y ago
    They got sick of philosophers asking tough questions probably.
  - mbivert 2y ago
    > How did we come to the point where we relegated philosophy to be the study of only the things not connected with reality? If it deals with reality, then it's in the realm of science; science being the superior form to tackle such things, there's simply no reasons to involve "philosophy". The only room left for philosophy is thus wherever science doesn't operate. Not that I think it's a good thing: the dogmatic, rigid, mindset advocated by contemporary institutionalized science feels detrimental to a "lighter" approach to life: it's as if people don't have the right to ponder about existence on their own anymore; it's child's play if it's not done in such and such a way.
    - ithkuil 2y ago
      A lot of good science can be done without much philosophy. But you can't have good philosophy if you intentionally avoid science. I regained respect in philosophy by reading the work of philosophers like Dan Dennet who break that unfortunate cliché where philosophy has been stuck to only ponder at the left-overs of science and instead embrace science and apply sound philosophical thinking to navigate the consequences of what we discovered about reality.
      - mbivert 2y ago
        > A lot of good science can be done without much philosophy. > But you can't have good philosophy if you intentionally avoid science. As always, it all depends on the definition of "philosophy" and "science". If it's the "love of wisdom" and "knowledge" respectively, then I doubt hardly anything of value can be produced without both philosophy and science; and philosophy should be of greater value (e.g. Socrates' "I know that I know nothing").
0xTJ 2y ago
Philosophy isn't relevant here, this is talking about science and theorizing about the function of real structures in our brains.
- nonrandomstring 2y ago
  piffle
- delichon 2y ago
  That statement is a theory of empirical philosophy.
exe34 2y ago
So like Narnia looking out of the cupboard?
delichon 2y ago
Sucks that this fascinating question is getting downvoted. It seems natural to wonder what the "real" world looks like, given that we see it through such a convoluted set of lenses. Does our sense of time and motion emerge through this latent sequence alone, or are they properties of any kind of memory? Are emotions part of this peculiar path of evolution or a part of sentience? Is sentience dependent on latent sequences?
- smokel 2y ago
  Thank you for your support. I probably shouldn't have mentioned God, and I guess my remark was a little bit too concise. I'm not too familiar with contemporary philosophy, but recent insights brought on by LLMs sure made me want to revisit Wittgenstein. To take it even further (and risk a few more downvotes? :), are we entering a time where idealism can get a new foundation? It has always seemed pretty suspicious that science is so good at explaining natural phenomena [1]. Combine that with the idea that our brains cannot do more than basic logic [2], and one could easily conclude that we get to see only a very small part of totality. [1] https://en.wikipedia.org/wiki/The_Unreasonable_Effectiveness_of_Mathematics_in_the_Natural_Sciences https://en.wikipedia.org/wiki/The_Unreasonable_Effectiveness... [2] https://en.wikipedia.org/wiki/Church%E2%80%93Turing_thesis https://en.wikipedia.org/wiki/Church%E2%80%93Turing_thesis

fredgrott 2y ago

If you read Wolfram's work you see him talking about this several times...

observationist 2y ago

This is coming from Dileep George and the Jeff Hawkins adjacent theories around hierarchical temporal memory, cortical columns, and much of the higher level theory around what it is that the brain is doing in its smallest, repeated functional units. They split some time back, but they're both quite rigorous and have done exciting research. This paper goes over allocentric framing of learning, allowing cortical networks to be built through learning and thinking over time, driving a more complex and nuanced model of the world to be built throughout the networks in the brain, where the hippocampus seems to hold the long term memory, with connections that feed back up to nearly every region in the cortex. It's not complete, but it abstracts a level away from phenomenological observations like the notion of Jennifer Aniston cells, or mirror neurons, or things that occur as a consequence of some underlying functionality. We're getting much closer to a complete picture of the algorithms underlying human intelligence, and those may unlock human level machine intelligence, the understanding of consciousness, and all sorts of great medicine and technology. Google made a good choice in hiring Dileep George.

K0SM0S 2y ago
Agreed. Anecdotal (but deep) research led me to postulate that our entire "inner world", for lack of a better word, is an emergent construction based on a fundamentally spatiotemporal encoding of the external world. This assumes that feeding and motility, i.e., a geometric interpretation of the external world, is among the first 'functions' of living organisms in the evolutionary order. They subsequently became foundational for neuronal systems when these appeared about 500 million years ago. The hypothesis was informed by language notably, where most things are defined in spatial terms and concepts (temporal too, though more rarely), as if physical experiences of the world were the building blocks of thinking, really. A "high" council, a "sub" culture, a "cover", an "adjacent" concept, a "bigger" love, a "convoluted" or "twisted" idea, etc. Representations in one's inner world are all about shape, position, and movement of things in some abstract space of sorts. This is exactly how I'd use a 4D modeling engine to express a more 'Turing-complete' language, a more comprehensive experience (beyond movement: senses, intuitions, emotions, thoughts, beliefs…): use its base elements as a generator set to express more complex objects through composition in larger and/or higher-dim space. Could nature, Evolution, have done just that? Iteratively as it conferred survival advantages to these genes? What would that look like for each layer of development of neuronal—and later centralized "brain"—systems? Think as in geometric algebra, maybe; e.g., think how the metric of a Clifford algebra may simply express valence or modality, for those neuronal patterns to trigger the proper neurotransmitters. In biological brains, we've already observed neural graphs up to 11 dimensions (with a bimodal distribution peak around ~2.5D and ~3.8D iirc… Interestingly for sure, right within the spatiotemporal ballpark, seeing as we experience the spatial world in 2.5D more than 3, unlike fishes or birds). Jeff Hawkins indeed strongly shaped my curiosity, notably in "A Thousand Brains" and subsequent interviews. The paper here immediately struck me as very salient to that part of my philosophical and ML research—so kinda not too surprised there's history there. And I'm really going off on a tangent here, but I'm pretty sure the "tokenization problem" (as expressed by e.g. Karpathy) may eventually be better solved using a spatiotemporal characterization of the world. Possibly much closer to real-life language in biological brains, for the above reasons. Video pretraining of truly multimodal models may constitute a breakthrough in that regard, perhaps to synthesize or identify the "ideal" text divisions, a better generator set for (any) language.

oliyoung 2y ago

First thing that came to mind was the song-lines of Indigenous Australians, they code long journeys through country through narratives and songs, it's the macro form of this research https://en.wikipedia.org/wiki/Songline https://en.wikipedia.org/wiki/Songline

kovezd 2y ago

I've had the theory that our identity begins as an extension of the representation of space. We are simply the node at the center in a coordinate system, connected to the same emotions, rewards, and memories that every other node in the graph.

HarHarVeryFunny 2y ago
Pretty sure our identify is just that of the actor behind our own actions. i.e. Our brain models causal relationships, sees the correlation between it's own pre-action thoughts and the following action, and therefore models itself as an actor/causal agent responsible for these thoughts and actions.
- borbulon 2y ago
  Thank you for this, it’s stirred up a considerable amount of thought in me, but I would also say that my immediate reaction is that > its own pre-action thoughts and the following action Can also be a sort of spatial processing

marmaduke 2y ago

> CSCGs build on top of cloned HMMs by augmenting the model with the actions of an agent. pretty interesting take, and reminds me of the models that Karl Friston and many colleagues make under the umbrella term "active inference", involving free energy minimization.

altairprime 2y ago

If you read nothing else in this paper, read the first two diagrams.