Ah, yes, this took me a long time to grok. It’s subtle and not explained well in most of the literature IMO. Let me take a crack at it.
When you’re talking about agents, you’re talking about the domain of coupled dynamic systems. This can be modeled as a set of internal states, a set of blanket states divided into active and sensory, and a set of external states (it’s worth looking at this diagram to get a visual). When modeling an agent, we model the agent as the combination of all internal states and all blanket states. The active states are how the agent takes action, the sensory states are how the agent gets observations, and the internal states have their own dynamics as a generative model.
But how did we decide which part of this coupled dynamic system was the agent in the first place? Well, we picked one of the halves and said “it’s this half”. Usually we pick the smaller half (the human) rather than the larger half (the entire rest of the universe) but mathematically there is no distinction. From this lens they are both simply coupled systems. So let’s reverse it and model the environment instead. What do we see then? We see a set of states internal to the environment (called “external states” in the diagram)...and a bunch of blanket states. The same blanket states, with the labels switched. The agent’s active states are the environment’s sensory states, the agent’s sensory states are the environment’s active states. But those are just labels, the states themselves belong to both the environment and the agent equally.
OK, so what does this have to do with a rock? Well, the very surface of the rock is obviously blanket state. When you lightly press the surface of the rock, you move the atoms in the surface of the rock. But because they are rigidly connected to the next atoms, you move them too. And again. And again. The whole rock acts as a single set of sensory states. When you lightly press the rock, the rock presses back against you, but again not just the surface. That push comes from the whole rock, acting as a single set of active states. The rock is all blanket, there is no interiority. When you cut a layer off the surface of a rock, you just find...more rock. It hasn’t really changed. Whereas cutting the surface off a living agent has a very different impact: usually the agent dies, because you’ve removed its blanket states and now its interior states have lost conditional independence from the environment.
All agents have to be squishy, at least in the dimensions where they want to be agents. You cannot build something that can observe, orient, decide, and act out of entirely rigid parts. Because to take information in, to hold it, requires degrees of freedom: the ability to be in many different possible states. Rocks (as a subset of crystals) do not have many internal degrees of freedom.
Side note: Agents cannot be a gas just like they can’t be a crystal but for the opposite reason. A gas has plenty of degrees of freedom, basically the maximum number. But it doesn’t have ENOUGH cohesion. It’s all interior and no blanket. You push your hand lightly into a gas and...it simply disperses. No persistent boundary. Agents want to be liquid. There’s a reason living things are always made using water on earth.
tldr: rocks absolutely have a persistent boundary, but no interiority. agents need both a persistent boundary and an interiority.
Re: Black Holes specifically...this is pure speculation because they’re enough of an edge case I don’t know if I really understand it yet...I think a Black Hole is an agent in the same sense that our whole universe is an agent. Free energy minimization is happening for the universe as a whole (the 2nd law of thermodynamics!) but it’s entirely an interior process rather than an exterior one. People muse about Black Holes potentially being baby universes and I think that is quite plausible. Agents can have internal and external actions, and a Black Hole seems like it might be an agent with only internal-actions which nevertheless persists. You normally don’t find something that’s flexible enough to take internal action, yet rigid enough to resist environmental noise—but a Black Hole might be the exception to that, because its dynamics are so powerful that it doesn’t need to protect itself from the environment anymore.
If you built a good one, and you knew how to look at the dynamics, you’d find that the agent in the computer was in a “liquid” state. Although it’s virtualized, so the liquid is in the virtualization layer.
Ah, yes, this took me a long time to grok. It’s subtle and not explained well in most of the literature IMO. Let me take a crack at it.
When you’re talking about agents, you’re talking about the domain of coupled dynamic systems. This can be modeled as a set of internal states, a set of blanket states divided into active and sensory, and a set of external states (it’s worth looking at this diagram to get a visual). When modeling an agent, we model the agent as the combination of all internal states and all blanket states. The active states are how the agent takes action, the sensory states are how the agent gets observations, and the internal states have their own dynamics as a generative model.
But how did we decide which part of this coupled dynamic system was the agent in the first place? Well, we picked one of the halves and said “it’s this half”. Usually we pick the smaller half (the human) rather than the larger half (the entire rest of the universe) but mathematically there is no distinction. From this lens they are both simply coupled systems. So let’s reverse it and model the environment instead. What do we see then? We see a set of states internal to the environment (called “external states” in the diagram)...and a bunch of blanket states. The same blanket states, with the labels switched. The agent’s active states are the environment’s sensory states, the agent’s sensory states are the environment’s active states. But those are just labels, the states themselves belong to both the environment and the agent equally.
OK, so what does this have to do with a rock? Well, the very surface of the rock is obviously blanket state. When you lightly press the surface of the rock, you move the atoms in the surface of the rock. But because they are rigidly connected to the next atoms, you move them too. And again. And again. The whole rock acts as a single set of sensory states. When you lightly press the rock, the rock presses back against you, but again not just the surface. That push comes from the whole rock, acting as a single set of active states. The rock is all blanket, there is no interiority. When you cut a layer off the surface of a rock, you just find...more rock. It hasn’t really changed. Whereas cutting the surface off a living agent has a very different impact: usually the agent dies, because you’ve removed its blanket states and now its interior states have lost conditional independence from the environment.
All agents have to be squishy, at least in the dimensions where they want to be agents. You cannot build something that can observe, orient, decide, and act out of entirely rigid parts. Because to take information in, to hold it, requires degrees of freedom: the ability to be in many different possible states. Rocks (as a subset of crystals) do not have many internal degrees of freedom.
Side note: Agents cannot be a gas just like they can’t be a crystal but for the opposite reason. A gas has plenty of degrees of freedom, basically the maximum number. But it doesn’t have ENOUGH cohesion. It’s all interior and no blanket. You push your hand lightly into a gas and...it simply disperses. No persistent boundary. Agents want to be liquid. There’s a reason living things are always made using water on earth.
tldr: rocks absolutely have a persistent boundary, but no interiority. agents need both a persistent boundary and an interiority.
Re: Black Holes specifically...this is pure speculation because they’re enough of an edge case I don’t know if I really understand it yet...I think a Black Hole is an agent in the same sense that our whole universe is an agent. Free energy minimization is happening for the universe as a whole (the 2nd law of thermodynamics!) but it’s entirely an interior process rather than an exterior one. People muse about Black Holes potentially being baby universes and I think that is quite plausible. Agents can have internal and external actions, and a Black Hole seems like it might be an agent with only internal-actions which nevertheless persists. You normally don’t find something that’s flexible enough to take internal action, yet rigid enough to resist environmental noise—but a Black Hole might be the exception to that, because its dynamics are so powerful that it doesn’t need to protect itself from the environment anymore.
An agent created in a computer would be an exception to that?
If you built a good one, and you knew how to look at the dynamics, you’d find that the agent in the computer was in a “liquid” state. Although it’s virtualized, so the liquid is in the virtualization layer.