[Intuitive self-models] 3. The Homunculus

post by Steven Byrnes (steve2152) · 2024-10-02T15:20:18.394Z · LW · GW · 0 comments

Contents

  3.1 Post summary / Table of contents
  3.2 “The Conventional Intuitive Self-Model”
  3.3 The “vitalistic force” intuition
    3.3.1 What is the “vitalistic force” intuition?
    3.3.2 “Vitalistic force” is built from the interoceptive feeling of surprise (i.e. physiological arousal + prediction error), but is different from that feeling
    3.3.3 The “vitalistic force” intuition does not veridically correspond to anything at all
    3.3.4 The “wanting” intuition
    3.3.5 The intuition that “vitalistic force” and “wanting” seem to be present inside the brain algorithm itself
    3.3.6 The “vitalistic force” intuition contributes to bad takes about free will and artificial general intelligence
  3.4 The homunculus in contexts
    3.4.1 The homunculus, in the context of knowledge and assessments
    3.4.2 The homunculus, in the context of “self”
    3.4.3 The homunculus, in the context of technical neuroscience research
  3.5 What does the homunculus want?
    3.5.1 The homunculus centrally “wants” and “causes” X’s for which S(X) has positive valence
    3.5.2 An edge case: impulsive planning
    3.5.3 “I seek goals” versus “my goals are the things that I find myself seeking”
    3.5.4 Why are ego-dystonic things “externalized”?
  3.6 The homunculus concept does not veridically correspond to anything at all
  3.7 Where does it feel like the homunculus is located?
    3.7.1 Some people and cultures have a homunculus outside their head
    3.7.2 Mistaken intuition: “When I intuitively feel like the homunculus is in my head, I’m just directly feeling where my brain is”
    3.7.3 Mistaken intuition: “When I intuitively feel like the homunculus is in my head, I’m just feeling where my eyes see from, and my ears hear from”[16]
    3.7.4 So how does the homunculus wind up in a particular location?
    3.7.5 By the way, where is “awareness”?
  3.8 Conclusion
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3.1 Post summary / Table of contents

This is the third of a series of eight blog posts [? · GW], which I’m serializing over the next month or so. (Or email or DM [? · GW] me if you want to read the whole thing right now.)

So far in the series, Post 1 [LW · GW] established some foundations about intuitive self-models in general, and then Post 2 [LW · GW] talked about the specific intuitive self-model concept “conscious awareness”.

Now we’re ready to meet the protagonist starring in (most people’s) intuitive self-models—the mental concept that is conceptualized as being the root cause of many important mental events, especially those associated with “free will”. It’s the intender of intentions! It’s the decider of decisions! It’s the will-er of willing!

Following Dennett, I call this concept: “the homunculus”.^[1]

If you’re still not sure what I’m talking about, here are a couple more pointers:

• If “I exercise my free will to do X”, then, in my intuitive self-model, X was caused by the homunculus. By contrast, “reflexive” actions (“acting on instinct”, “blurting something out”, etc.) are usually conceptualized as not being caused by the homunculus—notwithstanding the fact that they are caused by the brain in real life.
• The terms “my self”, “my mind”, and “I” / “me” generally include the homunculus, but are often broader than that. For example, in the sentence “I don’t know what I’m doing”, the first “I” refers mainly to the homunculus, and the second “I” refers to the broader notion of my brain and body.

I’ll argue that you are already familiar with “the homunculus” as a pre-theoretical intuition. By the time we’re done with this post, “the homunculus” will still be a pre-theoretical intuition—that’s just what it is!—but hopefully it will be a pre-theoretical intuition that you’ll be better equipped to identify, understand, and question.

Here’s the post outline:

• Section 3.2 explains why I said “most people’s intuitive self-models” instead of “everyone’s intuitive self-models” at the top of the post. For example, in Dissociative Identity Disorder (Post 5), there’s more than one homunculus concept! And in “awakening” (Post 6), the homunculus concept just disappears entirely! But in this post, we’re restricting attention to what I call the “Conventional Intuitive Self-Model”, which is the intuitive self-model that the vast majority of my readers have in their heads right now.
• Section 3.3 describes a property of our intuitive worlds that I call “vitalistic force”. As background, sometimes we treat our own feelings as intrinsic properties of things out there in the world—Arthur is handsome, Birthdays are exciting, Capitalism is bad, etc. When we apply that general principle to “the feeling of being surprised”, we get an intuition that objects can be intrinsically unpredictable. And that’s what I call “vitalistic force”. We intuitively ascribe “vitalistic force” (and the closely-related intuitive model of “wanting”) to live animals, to other people, and most importantly for our purposes, to the homunculus. Vitalistic force is an intuition in the “map”, but I’ll argue that it does not veridically (§1.3.2 [? · GW]) correspond to anything at all in the “territory”; I’ll suggest that this is the root cause of many bad takes on free will and artificial intelligence.
• Section 3.4 elaborates on what the “homunculus” concept is and isn’t, by putting it in the context of our knowledge and assessments, and in the context of our broader concept of “self”, and in the context of technical neuroscience research.
• Section 3.5 asks “what does the homunculus want”? I argue that it most centrally “wants” concepts X such that the self-reflective S(X) concept (see §2.2.3 [LW · GW]) has positive valence; this turns out to be related to brainstorming and planning how to make X happen. Relatedly, I explain why our ego-syntonic motivations tend to be “internalized” as “desires”, while our ego-dystonic motivations are “externalized” as “urges”.
• Section 3.6 argues for the counterintuitive claim that the homunculus, just like vitalistic force, does not veridically correspond to anything at all—which explains how different intuitive self-models can wildly modify the homunculus concept, or even do away with it altogether, as we’ll see in future posts.
• Section 3.7 delves into one particularly interesting aspect of the homunculus concept, and one which will come up again in future posts: the location of the homunculus. For the vast majority of people reading this post, you feel like when the homunculus does things, those things happen in your head. But interestingly, this is not universal. I’ll talk about why the homunculus has a location at all, and how it winds up in the head (in my culture), and also how it winds up not in the head in other cases.

3.2 “The Conventional Intuitive Self-Model”

If you read mainstream philosophical discourse on consciousness, free will, and so on, it’s overwhelmingly written by people with a generally similar intuitive self-model,^[2] and that’s the one I want to discuss in this post. I don’t know if it already has a name, so I’m naming it “The Conventional Intuitive Self-Model”.

It does include things like “consciousness”, “qualia”, and a unified “self” with “free will”. It does not include experiences like trance, or dissociation, or awakening, or hearing voices (the next four posts respectively), nor does it include (I presume) any of a zillion uncatalogued idiosyncrasies in people’s inner worlds.

The word “conventional” is not meant to indicate approval or disapproval (see §1.3.3 [? · GW]). It’s just the one that’s most common in my own culture. If you believe Julian Jaynes (a big “if”!—more on Jaynes in Post 7), the Conventional Intuitive Self-Model was rare-to-nonexistent before 1300–800 BC, at least in the Near East, until it gradually developed via cultural evolution and spread. And still today, there are plenty of cultures and subcultures where the Conventional Intuitive Self-Model is not in fact very conventional—e.g. a (self-described) anthropologist on reddit^[3] writes: “I work with Haitian Vodou practitioners where spirit possession, signs, hearing voices, seeing things, dreaming, card reading, etc. are all integral parts of their everyday lived reality. Hearing the lwa tell you to do something or give you important guidance is as everyday normal as hearing your phone ring…”.

Anyway, this post is limited in scope to The Conventional Self-Model, which I claim has a “homunculus” concept as described below. Then in subsequent posts, we’ll see how, in other intuitive self-models, this “homunculus” concept can be modified or even eliminated.

3.3 The “vitalistic force” intuition

3.3.1 What is the “vitalistic force” intuition?

As discussed in Post 1 [LW · GW], the cortex’s predictive learning algorithm systematically builds generative models that can predict what’s about to happen. Let’s consider three examples:

• (A) How well does the predictive learning algorithm do when you’re manipulating a rock in your hands? Great! After the generative models are built and refined a bit, there are no more surprises left—their predictions are basically perfect.
• (B) How well does the predictive learning algorithm do when you’re interacting with TV static? Also great! In this case, the generative models cannot predict each little random speck, but there’s also no need to—you rapidly stop paying attention to all the little random specks. In other words, the generative models remain agnostic about them; they don’t make any prediction one way or the other. But the generative models do successfully predict the gestalt appearance of the screen. So again, there will eventually be no important surprises left. Victory!
• (C) Finally, how well does the predictive learning algorithm do when you’re interacting with a live mouse? Not so good! Unlike the TV static, you’re probably drawn to pay attention to the motion of the mouse, rather than zoning it out. And unlike a rock, there’s no way to predict that motion in detail. It’s a never-ending fountain of surprise. The best the generative models can do is learn typical mouse behavior patterns, and expect to always be a bit surprised.

I think this last pattern—a prediction that something is inherently a source of continual important but unpredictable behavior—turns into its own generalized intuitive model that we might label “vitalistic force”^[4]. (Other related terms include “animated-ness” as opposed to “inanimate”, and maybe “agency”). Our intuitive models ascribe the “vitalistic force” intuitive property to various things, particularly animals and people, but also to cartoon characters and machines that “seem alive”.

I think the predictive learning algorithm rapidly and reliably invents “vitalistic force” as an ingredient that can go into intuitive models of people and animals. Then when there’s a new stream of important and unpredictable observations, a salient possibility is that it’s caused by or associated with some new agency possessing vitalistic force. For example, the ancient Greeks observed lightning, and attributed it to Zeus.

3.3.2 “Vitalistic force” is built from the interoceptive feeling of surprise (i.e. physiological arousal + prediction error), but is different from that feeling

Again, vitalistic force is rooted in the interoceptive sensation of being surprised—probably some combination of physiological arousal and salient prediction error. But it’s different from that sensation. Vitalistic force is “part of the map” (it’s part of the generative model space in the cortex), whereas actually being surprised is “part of the territory” (it’s one of the sensory inputs that the generative models are built to predict^[5]).

Now, suppose my shirt is white. I intuitively think of the whiteness as being a property of the shirt, out in the world, not as a belief about the shirt within my own mind. As another example, valence is an interoceptive sensory input [LW · GW], but it doesn’t seem to be an assessment that exists within my own mind, but rather, a property of things in the world. For example, if whenever I think of capitalism, it calls forth a reaction of positive / negative valence, then I might well say “capitalism is good / bad”, as if the the “goodness” or “badness” were a kind of metaphysical paint^[6] that’s painted onto “capitalism” itself. (See: “The (misleading) intuition that valence is an attribute of real-world things” [LW · GW].). Similarly, we say that a joke is funny, that a person is beautiful, that a movie is scary, that a hickey is embarrassing, and so on—each of your interoceptive sensations turns into its own color of metaphysical paint that gets painted onto (your conception of) the world outside yourself. (Cf. “mind projection fallacy” [? · GW].^[7])

Back to the case at hand. “Surprisingness” is an interoceptive input in my own brain, but in our intuitive models, it turns into a kind of metaphysical paint that seems to be painted onto things in the world, outside our own brain. And that metaphysical paint is what I call “vitalistic force”.

Now, if my white shirt happens to have a red flashlight shining on it right now, then when I look down at it, my current sensory inputs are more typical of the “red” concept, not white. But I don’t think of my shirt as actually being red. I know it’s still a white shirt. Instead, those red visual inputs are explained away by a different ingredient in my intuitive model of the situation—namely, the red flashlight.

By the same token, it’s entirely possible for me to be actually surprised when looking at the outputs of a complex clockwork contraption that I don’t understand, but to simultaneously model the contraption itself as lacking any “surprisingness” / “vitalistic force” metaphysical paint, within my intuitive model. Instead, the surprising feeling that I feel would be explained away by a different ingredient in my intuitive model of the situation—namely, my own unfamiliarity with all the gears inside the contraption and how they fit together.

I think you can get a sense for what I’m saying by watching those mesmerizing videos of the nanomachines powering a cell (e.g. 1, 2), and then try to envision a worm as an unfathomably complex clockwork contraption of countless tiny nanomachines. That’s a really different intuitive model from how you normally think of a worm, right? It’s got a different “feel”, somehow. I think a big part of that different “feel” is the absence of the “vitalistic force” metaphysical paint in your intuitive model. It feels “inanimate”.

3.3.3 The “vitalistic force” intuition does not veridically correspond to anything at all

As in §1.3.2 [? · GW], “veridical” refers to “map–territory correspondence”. Vitalistic force is in the “map”—our intuitive models of how the world works. Is there some corresponding thing in the territory? Some objective, observer-independent thing that tracks the intuition of vitalistic force?

Nope!

Instead, I’d say:

• Sometimes the most salient and intuitively-plausible model of a situation (from a particular person’s perspective) involves vitalistic force—i.e., things having intrinsic surprising-ness.
• And sometimes the most salient and intuitively-plausible model of a situation does not involve vitalistic force—i.e., nothing present seems to have intrinsic surprising-ness, although there can still be surprises and unpredictability due to other factors like unfamiliarity, limited information, not paying attention, etc.

…And I think that’s all there is to say; this intuitive distinction doesn’t track anything in the real world.^[8]

3.3.4 The “wanting” intuition

Related to the “vitalistic force” intuition is the “wanting” intuition. The “wanting” intuition involves a frame “X wants Y”, defined as follows:

• X has vitalistic force—it seems to have an intrinsic property of taking actions that we can’t reliably predict.
• …But we can predict that X’s unpredictable actions will tend to result in Y.

(Related: Demski’s notion of “Vingean agency” [LW · GW].)

For example, if I’m watching someone sip their coffee, I’ll be surprised by their detailed bodily motions as they reach for the mug and bring it to their mouth, but I’ll be less surprised by the fact that they wind up eventually sipping the coffee.

This seems like the kind of general pattern that a predictive learning algorithm should readily learn.

The “wanting” intuition and the “vitalistic force” intuition seem to be closely intertwined, with each strongly implying the other. Presumably this comes out of their observed correlation in the world—for example, the unpredictability of people and animals is associated with both “wanting” and (very mild) physiological arousal; conversely, the unpredictability of TV static and raindrops is associated with neither “wanting” nor physiological arousal.

3.3.5 The intuition that “vitalistic force” and “wanting” seem to be present inside the brain algorithm itself

Let’s say a toddler has already internalized the “vitalistic force” and “wanting” intuitions by observing other humans and animals. Then they observe their own minds.^[9] What do they see?

Well, one thing that happens in the mind is: sometimes a thought X becomes active, and has positive valence. This automatically kicks off brainstorming / planning about how to make X happen (see here [LW · GW] & here [LW · GW] for mechanistic details), and if a good plan is found by that process, then X is liable to actually happen. Moreover, we can’t predict what the brainstorming / planning results will be in advance—when those thoughts appear, they will be surprising (as discussed in §1.4.1 [? · GW]).

So we have all the ingredients of “vitalistic force” and “wanting” (§3.3.4 above)—important unpredictability, with an ability to predict certain end-results better than the path by which they actualize. Thus, our intuitive models fit these kinds of observations to the hypothesis that there’s a vitalistic-force-carrying entity in our minds that “wants” X.

After Dennett, I call this entity “the homunculus”.

To be clear, it’s not a hard-and-fast rule that there must be only one vitalistic-force-carrying entity in our intuitive self-model. Rather, it’s an aspect of how I’m defining the Conventional Intuitive Self-Model (CISM, §3.2 above), and I’m restricting this post to the CISM. In fact, even someone mainly in the CISM might occasionally “animate” some non-homunculus aspect of their minds—“my OCD is telling me to buy squirrel repellent, just in case”—and there’s a spectrum of how literal versus metaphorical those kinds of statements feel to the speaker. We’ll see more dramatic departures from CISM in later posts.

More on the homunculus in a bit. But first…

3.3.6 The “vitalistic force” intuition contributes to bad takes about free will and artificial general intelligence

When people ask me my opinion about free will, I immediately launch into a spiel along the following lines:

Rice’s theorem (a.k.a. computational irreducibility) says that for most algorithms, the only way to figure out what they’ll do with certainty is to run them step-by-step and see.

So it’s kinda misleading to say “the laws of physics predict that the person will decide to take action A1”. A better description is: “the laws of physics predict that the person will think it over, ponder their goals and preferences and whims, and then make a decision, and it turns out the decision they made is … [and then we pause and watch as the person takes action A1] … well, I guess it was Action A1”. And if the person had decided A2, then evidently A2 would have been the prediction of the laws of physics! In other words, if the laws of physics were deterministic, that determinism would run through the “execution of free will”; it wouldn’t circumvent it.^[10]

…OK, that’s my spiel. I think it’s a nice spiel! But it’s entirely omitting the part of the story that’s most relevant to this series.

Instead let’s ask: Why do people’s intuitions push so hard against the possibility of voluntary decisions being entirely determined by the workings of step-by-step algorithmic mechanisms under the hood? I think it gets to a non-veridical aspect of the intuitive model.

• The intuitive model says that the decisions are caused by the homunculus, and the homunculus is infused with vitalistic force and hence unpredictable. And not just unpredictable as a state of our limited modeling ability, but unpredictable as an intrinsic property of the thing itself—analogous to how it’s very different for something to be “transparent” versus “of unknown color”, or how “a shirt that is red” is very different from “a shirt that appears red in the current lighting conditions”.
• By contrast, as in §3.3.2 above, if you look at a clockwork contraption that you don’t understand, you’ll be surprised by its behavioral outputs, but your intuitive model will say that there’s no “surprisingness” / “vitalistic force” metaphysical paint within the clockwork contraption itself. Instead, the surprise is explained away (in your intuitive model) as arising from your unfamiliarity with the details of the contraption.

So if you’re imagining the vitalistic-force-carrying homunculus, and you’re also simultaneously imagining that there’s a deterministic clockwork contraption under the hood … oops, you can’t. Those model ingredients contradict each other. It’s like trying to imagine a square circle, or a perfectly stationary explosion.

People tend to have a very-deeply-rooted (i.e., very-high-prior-probability) belief in the Conventional Intuitive Self-Model. After all, this model has issued hundreds of millions of correct predictions over their lifetime. Talk about a strong prior! So they’re naturally very resistant to accept any claim that’s incompatible with this intuitive model. And the idea that there is any mechanism under the hood that leads to “decisions”—whether we call that mechanism “the laws of physics”, or “the steps of an algorithm”, or “the dynamics of neurons and synapses”, or anything else—would be in violation of that intuitive model.

(Side note: if you’re wondering what free will actually is, if anything, I’ll leave that to the philosophers—see §1.6.2 [? · GW].)

Relatedly, you’ll sometimes hear things like “AI is just math” as an argument that Artificial General Intelligence (as I define it) [LW · GW] is impossible,^[11] i.e. that no AI system will ever be able to do the cool things that human brains can do, like invent new science and technology from scratch, creatively make and execute plans to solve problems, anticipate and preempt roadblocks, collaborate at civilization scale, and so on.

I think part of what’s happening there is that when these people think of humans, they see vitalistic force, and when they think of algorithms running on computer chips, they see an absence of vitalistic force. And it seems to follow that of course the algorithms-on-chips can’t possibly do those above things that human scientists and entrepreneurs do every day. Those things require vitalistic force!

Indeed (these people continue), if you are stupid enough to think AGI is in fact possible, it’s not because you don’t see vitalistic force in human brains (a possibility that doesn’t even cross their minds!), but rather that you do see vitalistic force in AI algorithms. So evidently (from their perspective), you must just not understand how AI works! After all, we can all agree that if you understood every hardware and software component of a chip running an AI algorithm, then you would correctly see that it’s “just” a “mechanism”, free of vitalistic force. Of course, these people don’t realize that a brain, or indeed a global civilization of billions of human brains and bodies and institutions, is “just” a “mechanism”, free of vitalistic force, as well.^[12]

3.4 The homunculus in contexts

“Homunculus” means “little person”. It’s part of your intuitive self-model. To better explain what it is and isn’t, here are some points of clarification:

3.4.1 The homunculus, in the context of knowledge and assessments

The homunculus is definitely not the same as “everything in my brain” or “everything in my mind”. To give three examples:

• Ego-syntonic “desires” are conceptualized as being internal to the homunculus, whereas ego-dystonic “urges” are conceptualized as intrusions upon the homunculus from the outside. But in reality, both are part of my brain algorithms.
• A self-reflective explicit belief like “I’m pretty sure that the capital of Burundi is Gitega” would be conceptualized as being internal to the homunculus; whereas an implicit belief like [implicit expectation that the bedroom doorknob is hard to twist] would be conceptualized as being external to the homunculus, and instead a property of the doorknob itself. But in reality, both kinds of beliefs are part of my brain algorithms.
• Likewise, as mentioned in §3.3.2 above, a self-reflective explicit preference / judgment (“I hate Jo”) would be conceptualized as being internal to the homunculus; whereas an implicit preference / judgment like “Jo sucks” would be conceptualized as being external to the homunculus, and instead a property of Jo herself. But in reality, both kinds of judgments are part of my brain algorithms.

3.4.2 The homunculus, in the context of “self”

The homunculus, as I use the term, is specifically the vitalistic-force-carrying part of a broader notion of “self”:

There’s a whole lot more detailed structure that I’m glossing over in that diagram. For example, in my mind, I think of goals as somehow “inside” the homunculus. In some respects, my body feels like “a thing that the homunculus operates”, like that little alien-in-the-head picture at the top of the post, whereas in other respects my body feels connected to the homunculus in a more intimate way than that. The homunculus is connected to awareness both as an input channel (it “watches the stream-of-consciousness (§2.3 [LW · GW]) on the projector screen of the Cartesian theater”, in the Consciousness Explained analogy), and as an output (“choosing” thoughts and actions). Moods might be either internalized (“I’m really anxious”) or externalized (“I feel anxiety coming on”), depending on the situation. (More on externalization in §3.5.4 below.) And so on.

3.4.3 The homunculus, in the context of technical neuroscience research

I find that the homunculus intuition also comes up in my neuroscience work, almost always for the worse. In particular, if you’re thinking about neuroscience, and if you’re tempted to give the homunculus some important role in how brain algorithms work at a fundamental level, then you’re definitely on the wrong track! The homunculus is one of a zillion learned concepts in the cortex—it’s at the trained model level, not the learning algorithm level (see §1.5.1 [LW · GW])—and thus you should expect the homunculus to have a fundamentally similar kind of role in innate low-level brain algorithms as other learned concepts like “Taylor Swift” or “lithium ion battery”—i.e., a rather incidental role!

One example of how people mess this up is summarized in this handy chart:

If you’re trying to think carefully about brain algorithms—e.g. you want to reverse-engineer what the cortex does, versus the brainstem, etc.—I claim that the fundamental division in this chart is between involuntary and voluntary actions. This division relates to valence [LW · GW], and is right at the core of the reinforcement learning algorithm built into your brain. But in our homunculus-centric intuitions, we’re instead drawn to incorrectly see the fundamental division as between things that the homunculus causes, versus things the homunculus does not cause.

(Neuroscientists obviously don’t use the term “homunculus”, but when they talk about “top-down versus bottom-up”, I think they’re usually equating “top-down” with “caused by the homunculus” and “bottom-up” with “not caused by the homunculus”.)

Here’s another example: The neuro-AI researcher Jeff Hawkins incorrectly conflates the within-homunculus-versus-outside-homunculus intuitive division, with the cortex-versus-brainstem neuroanatomical division. This error leads him to make flagrantly self-contradictory claims, along with the dangerously incorrect claim that the brain-like AIs he’s trying to develop will have nice prosocial motivations by default. For details see here [LW · GW].

3.5 What does the homunculus want?

3.5.1 The homunculus centrally “wants” and “causes” X’s for which S(X) has positive valence

Back in §2.6 [? · GW], I argued that there’s a common sequence of two thoughts:

• STEP 1: There’s a self-reflective thought S(A), for some action-program A (either motor-control or attention-control), and this thought has positive valence;
• STEP 2 (a fraction of a second later): The non-self-reflective (a.k.a. object-level) thought A occurs, and this thought also has positive valence, and thus the action A actually happens.

In the Conventional Intuitive Self-Model, we conceptualize this as follows:

• Why is there positive valence in STEP 1? Because the homunculus wants A to happen right now.
• Why did A happen in STEP 2? Because the homunculus did it.

And we might describe this process as “I exercised my free will to do A”, in an intentional, self-aware way.

Another illustrative case is where S(A) has positive valence, but A has negative valence. An example would be: “I really wanted and intended to step into the ice-cold shower, but when I got there, man, I just couldn’t.” Recall that a positive-valence self-reflective S(A) will pull upwards on the valence of the action A itself (§2.5.2 [LW · GW]). But if A is sufficiently demotivating for other reasons, then its net valence can still be negative, and thus it won’t happen.

Why am I centering my story around the valence of S(X), rather than the valence of X?

Part of the answer is a “refrigerator-light illusion”. “Wanting” behavior involves brainstorming / planning towards some goal X. When we turn our attention to the “wanting” itself, in real-time, we incidentally make the self-reflective S(X) thought highly active and salient. If that S(X) thought has negative valence, then the whole brainstorming / planning process starts feeling demotivating (details here [LW · GW]), so we’ll stop “wanting” X and start thinking about something else instead. Whereas if S(X) has positive valence, we can continue “wanting” X even while noticing what’s happening. So we can only “directly observe” what wanting X looks like in cases where S(X) has positive valence.

Another part of the answer is that positive-valence S(X) unlocks a far more powerful kind of brainstorming / planning, where attention-control is part of the strategy space. I’ll get into that more in Post 8.

Meanwhile, it might help to see the opposite case:

3.5.2 An edge case: impulsive planning

Consider an example of an X which is itself positive valence, but where the corresponding self-reflective S(X) thought is negative valence—say, X = smoking a cigarette, when I’m trying to quit.

Let’s say the idea X becomes active in my mind. Since it has positive valence, it kicks off brainstorming-towards-X (see §3.3.5 above)—for example, if the cigarette is at the bottom of my dad’s bag, then an idea might pop into my head that I can remove all the items from the bag, get the cigarette, and put the items back. That plan seems appealing, so I do it. But the whole thing is impulsive.

How do I describe what just happened?

I might say “I got the cigarette unthinkingly”. But that’s a pretty weird thing to say, right? I don’t really believe that I concocted and executed a skillful multi-step foresighted plan without “thinking”, right??

Alternatively, if you ask me whether what I did was “deliberate or accidental”, well, it sure wasn’t accidental! But calling it a “deliberate act” isn’t quite right either.

I certainly wouldn’t say “I exercised my free will to get the cigarette”.

A better description than “I got the cigarette unthinkingly” might be “I got the cigarette unreflectively”—specifically, I’m saying that the self-reflective S(cigarette) thought did not activate during this process.

Anyway, there’s clearly “wanting” and “vitalistic force” involved in the construction and execution of the cigarette-retrieval plan. So my above claim that the homunculus “wants” X’s for which S(X) has positive valence is evidently a bit oversimplified. Or actually, maybe that is the intuitive model, and people just squeeze these kinds of poorly-fitting edge-cases into that intuitive model as best they can—maybe they’ll say “I wasn’t myself for a moment”, as if a different homunculus had temporarily subbed in!

3.5.3 “I seek goals” versus “my goals are the things that I find myself seeking”

As in §3.3.6 above, the “vitalistic force” intuition forbids the existence of any deterministic cause, seen or unseen, upstream of “wanting” behavior. (Probabilistic upstream causes, like “hunger makes me want food”, are OK. But the stronger such predictions get, the more they seem intuitively to undermine “free will”.)

This constraint on intuitive models leads to some systematic distortions, as shown in this diagram:

So within the Conventional Intuitive Self-Model,

• “I seek things that I want” seems normal and correct,
• “If I’m seeking something, then evidently that’s a thing I want” seems somewhere between “confused” and “a threat to my sense of agency”.

…But in terms of the real brain algorithm, I claim that these are more-or-less equivalent.

3.5.4 Why are ego-dystonic things “externalized”?

The main thing that the homunculus does is apply its vitalistic force towards accomplishing things it “wants”, via brainstorming / planning. So if there’s robust brainstorming / planning happening towards bungee jumping, then evidently (in our intuitive model) the homunculus “wants” to go bungee jumping. We call this an “internalized” desire. Conversely, if there’s robust brainstorming / planning happening towards not scratching an itch, but I scratch my itch anyway, then this is an “externalized” desire—the homunculus didn’t want the itch to get scratched, but the “urge” made it happen anyway.

We can apply this kind of thinking more generally. Compare the internalized “I become angry sometimes” with the externalized “I am beset by anger sometimes”. These are not synonymous: the latter, but not the former, has a connotation that there’s robust brainstorming / planning happening in my brain towards the goal of not being angry, possibly even while I’m angry. Admittedly, maybe I’m not spending much time doing such brainstorming / planning, or even any time, and maybe the brainstorming / planning isn’t effective. But still, the statement is still conveying something.

Combining this idea with §3.5.1, which says that robust brainstorming requires the corresponding self-reflective thoughts to have positive valence, and we wind up with the general picture that we tend to “internalize” things that reflect well upon ourselves (see §2.5.1 [LW · GW]), and “externalize” things that don’t.

Now, I used to think that the connection between ego-dystonic / ego-syntonic and externalized / internalized was the result of motivated reasoning [LW · GW]: it’s nice to think of bad things as being “outside ourselves”. But now I think it’s directly about motivation, treated as probabilistic evidence within the Conventional Intuitive Self-Model—as opposed to being about motivated reasoning.

I suppose that distinction doesn’t matter much—by and large, the “motivation-as-evidence” hypothesis and the “motivated reasoning” hypothesis both lead to the same downstream predictions. Well, maybe my “motivation-as-evidence” story is a better fit to the example I gave in §2.5.2 [LW · GW] of the tired person saying “Screw being ‘my best self’, I’m tired, I’m going to sleep”. This action is internalized, not externalized, and yet it goes directly against how the person would like to be perceived by themselves and others.

3.6 The homunculus concept does not veridically correspond to anything at all

As in §1.3.3 [? · GW], “veridical” refers to “map–territory correspondence”. Is there some kind of objective, observer-independent thing (in the “territory”) that corresponds to the “homunculus” concept (in the “map”)? I don’t think so.

To be clear:

• The core of the “homunculus” concept is that it’s an entity that carries “vitalistic force” (intrinsic unpredictability with no upstream cause) and applies that vitalistic force to accomplish things that it “wants”. That’s what I’m saying doesn’t exist “in the territory”.
• I’m not questioning that all the phenomena that we conventionally explain via the homunculus, are real phenomena that demand a real explanation (see Post 8).
• I’m not questioning that many other aspects of “self”—see diagram in §3.4.2—are veridical models of things.

The non-veridicality of the homunculus might seem unintuitive to you right now. I ask you to withhold judgment, and keep reading more of the series, where we’ll see:

• Intuitive self-models in which actions and intentions sometimes intuitively seem to be caused by an external agent, rather than by the homunculus (Post 4 on trance, Post 7 on hearing voices and other hallucinations)
• Intuitive self-models with several different homunculus concepts (Post 5 on Dissociative Identity Disorder)
• Intuitive self-models with no homunculus concept at all (Post 6 on awakening a.k.a. enlightenment)

…And especially hang on until Post 8, where I’ll discuss how to properly think about motivation, goals, and willpower, without attributing them to the homunculus concept.

3.7 Where does it feel like the homunculus is located?

For most people reading this, your intuitive models say that the homunculus is located in your head. For example, when you “exercise your free will” to “decide” to wiggle your fingers, that “decision” feels like it happens in your head.^[13]

Of course, in real life, yes the decision did happen in your head! That’s where your brain is!

But an important point that we’ll need for later posts in this series is that the homunculus-in-the-head intuition is by no means a requirement of an intuitive self-model.

You might find that kinda hard to imagine,^[14] so I’ll offer a few different lines of evidence and ways of thinking about it.

3.7.1 Some people and cultures have a homunculus outside their head

Here’s a source claiming that there’s substantial cross-culture variation in the intuitive spatial location of the homunculus:

The placing of the personality in a particular part of the body is cultural. Most Europeans place themselves in the head, because they have been taught that they are the brain. In reality of course the brain can’t feel the concave of the skull, and if we believed with Lucretius that the brain was an organ for cooling the blood, we would place ourselves somewhere else. The Greeks and Romans were in the chest, the Japanese a hand’s breadth below the navel, Witla Indians in the whole body, and even outside it. We only imagine ourselves as ‘somewhere’.

Meditation teachers in the East have asked their students to practise placing the mind in different parts of the body, or in the Universe, as a means of inducing trance.… Michael Chekhov, a distinguished acting teacher…suggested that students should practise moving the mind around as an aid to character work. He suggested that they should invent ‘imaginary bodies’ and operate them from ‘imaginary centres’… —Impro by Keith Johnstone (1979)

I definitely believe the second paragraph—I’ll get back to trance in Post 4 and meditation in Post 6. Is the first paragraph trustworthy? I tried to double check Johnstone’s claims:

Start with his claim about “the Japanese”. When I tried looking into it, I quickly came across the term shirikodama, which you should definitely google, as all the top English-language results are incredulous blog posts with titles like “The Soul in Your Butt, According to Japanese Legend” or “Shirikodama (n): Small Anus Ball”, full of helpful 18th-century woodblock prints of demons stealing people’s shirikodama via their butts.

Anyway, after a bit more effort, I found the better search term, hara, and lots of associated results that do seem to back up Johnstone’s claim (if I’m understanding them right—the descriptions I’ve found feel a bit cryptic). Note, however, that Johnstone was writing 45 years ago, and I have a vague impression that Japanese people below age ≈70 probably conceptualize themselves as being in the head—another victim of the ravages of global cultural homogenization, I suppose. If anyone knows more about this topic, please share in the comments!

Then I checked Johnstone’s claim about “Witla Indians”, but apparently there’s no such thing as “Witla Indians”. It’s probably a misspelling of something, but I don’t know what. Guess I’ll just ignore that part!

As for the Greeks and Romans, I gather that there’s more complexity and variation than Johnstone is letting on, but at least Lucretius seems to firmly support Johnstone’s claim:

Now I say that mind and soul are held in union one with the other, and form of themselves a single nature, but that the…lord in the whole body is the reason, which we call mind or understanding, and it is firmly seated in the middle region of the breast.^[15]

In summary, I think it’s probably true that the homunculus is conceptualized as being in different parts of the body in different cultures. But please comment if you know more than me.

3.7.2 Mistaken intuition: “When I intuitively feel like the homunculus is in my head, I’m just directly feeling where my brain is”

To understand the problem with this intuition, check out Daniel Dennett’s fun short story “Where Am I?”. He imagines his brain being moved into a jar, but attached to all its usual bodily inputs and outputs via radio link. He notes that he would still “feel” like he was in his head:

…While I recovered my equilibrium and composure, I thought to myself: “Well, here I am sitting on a folding chair, staring through a piece of plate glass at my own brain … But wait,” I said to myself, “shouldn’t I have thought, ‘Here I am, suspended in a bubbling fluid, being stared at by my own eyes’?” I tried to think this latter thought. I tried to project it into the tank, offering it hopefully to my brain, but I failed to carry off the exercise with any conviction. I tried again. “Here am I, Daniel Dennett, suspended in a bubbling fluid, being stared at by my own eyes.” No, it just didn’t work. …

Similarly, as Johnstone points out above, for most of history, people didn’t know that the brain thinks thoughts! But they were forming homunculus concepts just like us.

Indeed, different parts of the cortex are separated from each other by >15 cm. If a neuroscientist wants to know which cortical subregion is responsible for which types of computations, can they just “feel” where in their heads the different thoughts seem to be coming from? Of course not!

(Having said all that, our knowledge of brains is presumably not totally irrelevant to why we have a homunculus-in-the-head intuition—it probably lends that intuition some extra salience and plausibility. I’m just arguing that it’s not a requirement in practice.)

3.7.3 Mistaken intuition: “When I intuitively feel like the homunculus is in my head, I’m just feeling where my eyes see from, and my ears hear from”^[16]

(Just like the above, I’m open-minded to the eyes-and-ears factor being an influence on where the homunculus actually winds up in practice; I’m just arguing against it imposing a requirement on where the homunculus must be.)

One problem is that eyes and ears are only two of your senses, and the other senses provide ample evidence that it’s possible for sensory perceptions to have a “center” away from the homunculus. Close your eyes, reach out your hand, and feel the shape of some object. Your sensory perceptions are working fine, but all the action is happening “over there”, some distance away from “me” in the head. I see no reason in principle that vision and hearing couldn’t likewise be happening “over there”, with “me” being somewhere else, like the chest.

Or as another example, when you feel an excitement in the pit of your stomach, that feeling of excitement is happening “down there”, while vision is happening “right here”—and I’m saying that it could equally well be the other way around. And indeed, “the other way around” evidently has its own kind of intuitive compellingness, given that some cultures wind up doing it that way: Specifically, the pit of your stomach is intuitively tied to the feeling of physiological arousal, and hence to the willpower and sense-of-agency that are foundational to the homunculus.

3.7.4 So how does the homunculus wind up in a particular location?

The first question is: Why does the homunculus seem to have any location at all? Why can’t it be locationless, as are many other concepts like “justice”?

I’m not entirely sure. Here’s my best guess. Per above, the homunculus exists as the cause of certain thoughts and motor actions. We have a pretty deep-seated intuition, generalized from everyday experience, that causes of unusual motion require physical contact—think of grabbing the ball, pushing the door, stepping on the floor, etc.^[17] Presumably, this intuition implies that the homunculus must have a physical location in the body.

Then there’s a second question: what location? I think there are forces that make some possibilities more “natural” and “salient” than others—as mentioned above, your eyes and ears and brain are in the head, while your physiological arousal feels like it’s in the chest or abdomen. But most importantly, I think we pick it up from cultural transmission. Sometime in childhood,^[18] we learn from our friends and parents that there’s a homunculus in the head, and this becomes a self-fulfilling prophecy: the more that we conceptualize deliberate thoughts and actions as being caused by a homunculus-in-the-head, the more likely we are to assume that any other deliberate thoughts and actions are caused by it too (i.e., it becomes a strong prior).

In terms of the bistable perception discussion of §1.2 [LW · GW], imagine that you’ve been “seeing” the spinning dancer go clockwise, and never counterclockwise, thousands of times per day, day after day, month after month. After a while, it would become awfully hard to see it going counterclockwise, even if you wanted it to. By analogy, after a lifetime of practice conceptualizing a homunculus-in-your-head as the cause of deliberate thoughts and actions, it’s very hard (albeit not totally impossible) to imagine deliberate thoughts and actions as being caused by a homunculus-in-your-chest, or indeed by no homunculus at all. More on this in Posts 4 and 6.

3.7.5 By the way, where is “awareness”?

Everything so far has been about the intuitive location of the homunculus. Next, what about the other star of our intuitive self-models, namely the “awareness” concept of Post 2 [LW · GW]?

(Recall the X-versus-S(X) distinction of §2.2.3 [LW · GW]—I’m talking here about the intuitive location of the self-reflective “awareness” concept itself. Nobody is questioning the fact that, when I have an object-level thought about my coffee cup, my attention is over on the table.)

My current belief is that, in our intuitive models, the “awareness” concept, in and of itself, doesn’t really have a location! It’s more like “justice” and other such location-free concepts. Recall, above I suggested that the homunculus winds up with a location because it seems to cause bodily motion, and we have an intuition that motion-causation entails physical contact. But “awareness” is not a cause of any motion, so that argument doesn’t apply.

That said, I think the “awareness” concept winds up generally anchored to the head, but only because that’s where the homunculus is. Recall, the homunculus is intimately connected to “awareness”—the homunculus is causing things to be in awareness via attention control, and conversely the homunculus is taking in whatever is happening in awareness by “watching the projector screen in the Cartesian theater”, so to speak. So thoughts involving “awareness” itself almost always involve the homunculus too, and hence those thoughts seem to be about something happening in the head.

The main reason I believe all this is: the experiment has been done! I think there are lots of people who have an intuitive self-model involving an awareness concept, but not involving any homunculus concept. Those people generally report that, with the homunculus gone, suddenly the “awareness” concept is free to have any location, or no location at all.^[19] More on these “awakened” people in Post 6.

3.8 Conclusion

Between this and the previous post [LW · GW], we’ve covered the main ingredients of the Conventional Intuitive Self-Model. There’s much more that could be said, but this is a good enough foundation to get us to the fun stuff that will fill the rest of the series: trance, hallucinations, dissociation, and more. Onward!

Thanks Thane Ruthenis, Linda Linsefors, Seth Herd, and Justis Mills for critical comments on earlier drafts.

1. ^{^}

   In Consciousness Explained, Dennett emphasizes a passive role of the homunculus, where it “watches” the stream-of-consciousness; by contrast, I’m emphasizing the active role of the homunculus, where it causes the thoughts and actions that we associate with free will. I don’t think the passive role is wrong, but I do think it’s incidental—it’s not why the homunculus concept exists. Indeed, as we’ll see in Posts 4 (trance) and 6 (awakening), people empirically find that their intuitive homunculus concept dissolves away when the homunculus stops taking any actions for an extended period—despite the fact that the stream-of-consciousness is still there. In fact, I claim that Dennett’s stream-of-consciousness discussion can be lightly edited to make the same substantive points without mentioning the homunculus; and indeed, that’s exactly what I already did in §2.3 [LW · GW]. Specifically, Dennett could have talked about whether there’s a fact-of-the-matter about what’s on the “projector screen” of the “Cartesian Theater”, without talking about whether anyone is sitting in the theater audience. Still, at the end of the day, I think Dennett & I are talking about the same homunculus, so I borrowed his term instead of inventing a new one.

2. ^{^}

   Well, probably different philosophers-of-mind have different intuitive self-models to some extent. I imagine that this leads to people talking past each other.

3. ^{^}

   Yes I know that’s not a great source, but it passes various smell tests and is at least vaguely consistent with other things I’ve read about Haitian Vodou. Feel free to comment if you know more.

4. ^{^}

   I’m obviously borrowing the terminology from Vitalism, but I’m not a historian of science and don’t know (or care) if I’m using the term in the same way that the actual vitalists did.

5. ^{^}

   Things like physiological arousal are called “interoceptive” sensory inputs, as opposed to “exteroceptive” sensory inputs like hearing and vision. But from the perspective of the predictive learning algorithm, and the generative models that this algorithm builds, it hardly matters—a sensory input is a sensory input. See here [LW · GW] for related discussion.

6. ^{^}

   See also “The Meaning of Right” (Yudkowsky 2008) [LW · GW], who uses the metaphor of “XML tags” instead of “metaphysical paint”.

7. ^{^}

   I think this paragraph also has some overlap with Lisa Feldman Barrett’s notion of “affective realism”; more on Barrett here [LW · GW].

8. ^{^}

   Granted, one can argue that observer-independent intrinsic unpredictability does in fact exist “in the territory”. For example, there’s a meaningful distinction between “true” quantum randomness versus pseudorandomness. However, that property in the “territory” has so little correlation with “vitalistic force” in the map, that we should really think of them as two unrelated things. For example, in my own brain, the sporadic clicking of a geiger counter feels like an inanimate (vitalistic-force-free) “mechanism”, but is intrinsically unpredictable (from a physics perspective). Conversely, a rerun cartoon depiction of Homer Simpson feels like it’s infused with vitalistic force, but in fact it’s intrinsically fully predictable. Recall also that vitalistic force is related not only to unpredictability but also physiological arousal.

9. ^{^}

   From my (limited) understanding of the childhood development literature, it seems likely that the “vitalistic force” and “wanting” intuitions are learned from modeling other people and animals first, and then are applied to our own minds second. So that’s how I’m describing things in this section. There’s a school of thought (cf. Graziano & Kastner 2011 maybe?) which says that this ordering is profoundly important, i.e. that self-modeling is fundamentally a consequence of social modeling. I’m mildly skeptical of that way of thinking; the hypothesis that things get learned in the opposite order seems plenty plausible to me, even if it’s not my first guess. But whatever, that debate is not too important for this series.

10. ^{^}

    Of course, Rice’s theorem doesn’t rule out confident a priori probabilistic predictions of the outputs of a complex algorithm in particular cases. (Example: I predict with very high confidence that you won’t choose to stab yourself in the eye with a pen right now. Ha, not feeling so “free” now, right?) But our intuitions about “free will” come into force precisely when decisions are not overdetermined by circumstances.

11. ^{^}

    Very similar arguments are also sometimes put forward as an a priori reason to dismiss the possibility of AGI misalignment [LW · GW].

12. ^{^}

    Caveat for this paragraph: As usual, one should be extremely cautious with this kind of Bulverism. I think what I’m saying should be taken as a possibility for your consideration, when trying to understand any particular person’s perspective. But there are lots of people who confidently universally a priori dismiss the possibility of AGI and/or AI misalignment, for lots of different reasons. Yes, I think those people are all wrong, but hopefully it goes without saying that this “vitalistic force” discussion is not in itself proof that they’re all wrong! You still need to listen to their actual arguments, if any. Separately, there are people who dismiss the possibility of AGI and/or AI misalignment in reference to specific AI algorithms or algorithm classes. Those arguments are very different from what I’m talking about.

13. ^{^}

    As in §3.4.2 above, the homunculus is narrower than “me” or “my self”. Certainly it’s possible to “feel a yearning in your chest” and so on. But I will go out on a limb and say that, if a guy says “I was thinking with my dick”, he’s speaking metaphorically, as opposed to straightforwardly describing his intuitive self-model.

14. ^{^}

    As mentioned in §3.3.6 above, as a rule, everything about intuitive self-models always feels extremely compelling, and alternatives hard to imagine. After all, your intuitive self-models have been issuing predictions that get immediately validated thousands of times each day, for every day of your life, apart from very early childhood, so it’s a very strong prior.

15. ^{^}

    Fuller quote: “Now I say that mind and soul are held in union one with the other, and form of themselves a single nature, but that the head, as it were, and lord in the whole body is the reason, which we call mind or understanding, and it is firmly seated in the middle region of the breast. For here it is that fear and terror throb, around these parts are soothing joys; here then is the understanding and the mind. The rest of the soul, spread abroad throughout the body, obeys and is moved at the will and inclination of the understanding.” (source) (I think the word “head” in that excerpt is meant in the “person in charge” sense, not the anatomical sense.) (Note that the original is in Latin, and it’s possible that some important nuances were lost in translation.)

16. ^{^}

    Side note: This intuition would apply less to deaf people and blind people, and would not apply at all to deaf-blind people. Do those people feel like the homunculus is in their head? I can’t find good sources.

17. ^{^}

    See also Le Sage’s theory of gravitation which attempted to explain Newton’s law as a consequence of (more intuitive) physical contact forces; and see Richard Feynman’s comment that people ask him to explain bar magnets, but nobody ever asks him to explain physical contact forces (e.g. why your hand doesn’t pass through a chair), even though it should really be the other way around (electromagnetism is a fundamental law of nature, and physical contact forces are in turn a consequence of electromagnetism).

18. ^{^}

    Indeed, the indoctrination—oh sorry, acculturation—starts very early: when my kid was barely three years old, his preschool class was singing “Mat Man has one head, one head, one head, Mat Man has one head—so that he can think”!

19. ^{^}

    If you’re wondering how I got the impression that “awareness” becomes untethered from any particular location as soon as the homunculus is gone, it’s based on a bunch of things, but two examples that spring to mind are: “Centrelessness, Boundarylessness Phenomenology And Freedom From The Cage Of The Mind” by Thisdell, and the discussions of “awake awareness” and “witness” in Shift into Freedom by Kelly.

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