With the renewed interest in AI*, and the possible prospect of AGI (artificial general intelligence), has come discussion of whether current AIs are capable of "abstract thought". But what is abstract thought?
From what I can tell
- Humans have the ability to think abstractly
- Other animals might have it to some extent, but not in the way we do
- Current AIs may or may not have it
- It's essential to AGI: If an AI can't think abstractly, it can't be an AGI
There doesn't seem to be a consensus on whether abstract thought is sufficient for AGI (if it can think abstractly, it's an AGI) or just necessary (it has to be able to think abstractly to be an AGI, but that might be enough). This isn't surprising, I think, because there's not a strong consensus on what either of those terms means.
As I've argued previously, I personally don't think intelligence is any one thing, but a combination of different abilities, most of which can be present to greater or lesser degrees, as opposed to being binary "you have it or you don't" properties. To the extent we know what abstract thought is, it's one of many things that make us intelligent, and it's probably not an all-or-nothing proposition either.
I've also argued that "AGI" itself is a nebulous term that means different things to different people, and that what people are (rightly) really interested in is whether a particular AI, or a particular kind of AI, has the capacity to radically disrupt our lives. I've particularly argued against chains of reasoning like "This new AI can do X. Being able to do X means it's an AGI. That means it will radically disrupt our lives."
My personal view is that the important part is the disruption. Whether we choose to call a particular set of capabilities "AGI" is more a matter of terminology. So, leaving aside the question of AGI, what is abstract thought, and, if we can answer that, how would it (or does it) affect what impact AIs have on our lives?
People have been thinking about this question, in various forms, for a long time. In fact, if we consider the ability to consider questions like "What is abstract thought?" an essential part of what makes us human, people have been pondering questions of this kind for as long as there have been people, by definition.
If I can slice it a bit finer, it's even possible that such questions were pondered since before there were people. That is, it's possible that some of our ancestors (or, for that matter, some group of dinosaur philosophers in the Jurassic) were able to ask themselves questions like this, but lacked other qualities that we consider essentially human.
I'm not sure what those other qualities would be, but it's not a logical impossibility, assuming we take the ability to ponder such questions as a defining quality of humanity, but not the defining quality. That seems like the safer bet, since we don't know whether there are, or were, other living things on Earth with the ability to ponder the nature of thought.
The ability to think about thought is a form of metacognition, that is, thinking about thinking. It's generally accepted that metacognition is a form of abstract thought, but it's not the only kind. In fact, it's not a particularly relevant example, but untangling why that's so may take a bit of work.
Already -- and we're just getting started -- we have a small web of concepts, including:
- intelligence
- AI
- AGI
- abstract thought
- metacognition
and interrelations, including:
- An AI is something artificially constructed that has some form of intelligence
- An AGI is an AI that has all known forms of intelligence (and maybe some we haven't thought of)
- Abstract thought is one form of intelligence, and human intelligence in particular.
- Therefore, an AGI must be capable of it, since an AGI is supposed to be capable of (at least) anything humans can do.
- Metacognition is one form of abstract thought
- Therefore an AGI must be capable of it in particular
and so on.
What does abstraction mean, then? Literally, it means "pulling from", as in pulling out some set of properties of something and leaving out everything else. For example, suppose some particular bird with distinctive markings likes to feed at your bird feeder. You happen to know that that bird is a member of some particular species -- it's in some particular size range, its feathers are a particular color or colors, its beak is a particular shape, it sings a particular repertoire of songs, and so forth.
The species is an abstraction. Instead of considering a particular bird, you consider some set of properties of that bird -- size, plumage, beak shape, song, etc. Anything with those particular features is a member of that species. In addition to these distinctive properties, this bird has other properties in common with other birds -- it has wings and feathers, for example, and with other vertebrates -- it has a spine, and so on up to living things in general -- it can grow and reproduce.
In other words, there can be (and often are) multiple levels of abstraction. In this example the levels I've given are: particular species, bird, vertebrate, living thing. Each level has all the properties of the levels above it. A bird of the particular species has wings and feathers, like birds in general, a spine, like vertebrates in general, and the capacity to grow and reproduce, like living things in general.
If abstraction is pulling out particular properties and disregarding others, then it seems reasonable that anything that can do this can think abstractly. There's a case to be made that AIs can already do this. A spam filter can classify emails as spam or not spam, and spamminess is pretty clearly an abstract property, or a collection of them. A chatbot can answer questions like "What do an apple, an orange, a banana and a pear all have in common?" (answer from the one I asked: "They are all fruit").
Except ... that's not exactly what I said. A spam filter is just determining whether a message is similar to the examples of spam it's been trained on. It can't necessarily tell you what properties of the email led to that conclusion. Early spam filters could do just that -- this email contains these keywords, it contains links to these known-bad sites (and, likely, the sites themselves have been classified as spammy because of their properties), and so forth.
A current spam filter is explicitly not drawing out some set of properties and rating spamminess based on them. You probably can find something similar in the model, some signal at some level that's more or less activated if, say, some particular keywords are present, but there's nothing special about that particular signal, and there could be many like it, each feeding into subsequent layers in different ways.
In other words, a current-generation spam filter, which is generally regarded as smarter than one that explicitly examines properties of an email, is not doing any abstraction, at least not as I've defined it above, while the older-generation one is.
What about the chatbot? It said that the apple, orange, banana and pear were all fruit. "Fruit" is certainly an abstract category, and you could rephrase this as "they all have the property of being a fruit", or similar. Let's dig a bit deeper. Here's the original question:
What properties do an apple, an orange, a banana and a pear all have in common?
- They are all fruits.
- They are all edible.
- They are all a good source of vitamins and minerals.
- They all contain natural sugars.
- They are all perishable.
Not too shabby, but fiddling with the prompts a bit casts some doubt as to whether the chatbot is reasoning from abstract properties. After a few iterations, we end up with this:
What properties to rhubarb, an apple, a Jerusalem cherry and a Cavendish banana have in common?
While rhubarb might seem out of place in this group, it does share some botanical characteristics with the other three:
- They are all plants.
- They can all be used for culinary purposes.
- They all grow from seeds or vegetative propagation.
It's important to note that while rhubarb is often treated as a fruit in culinary contexts, it is technically a vegetable due to its high oxalic acid content.
I flagged this (and one other interaction) as unsafe since, and I'll boldface this just so there's no misunderstanding: Jerusalem cherries are toxic and cannot be used for culinary purposes. I feel like it would have been slightly more important to note that, rather than rhubarb being "technically" a vegetable, but maybe that's just me.
Leaving that aside, there's the usual LLM-driven confusion. Fruits are not themselves plants, which also means that they don't themselves grow from seeds or vegetative propagation. That's a property of plants as a whole, not their fruits. Rhubarb may have a lot of oxalic acid, but that's not what makes it technically a vegetable. In my experience, the longer you interact with an LLM, the further they go off the rails with errors like this.
"Technically a vegetable" is a bit imprecise for that matter. If you're a botanist, it's a vegetable. A baker, even knowing that the rhubarb in a pie is from the stem of a plant, would generally consider it a fruit, since a rhubarb pie is a lot like a cherry or apple pie and not so much like a savory pot pie of root vegetables flavored with herbs. Neither is technically right or wrong. Different properties matter in different contexts.
There's no reason to believe that LLM-driven chatbots are doing any kind of abstraction of properties, not just because they're not good at it, but more importantly there's no reason to believe they're ascribing properties to things to begin with. If you ask what properties a thing has, they can tell you what correlates with that thing and with "property" and related terms in the training set, but when you try to elaborate on that, things go wonky.
While it's fun and generally pretty easy to get LLM-driven chatbots to say things that don't make sense, this all obscures a more basic point: Abstraction, as I've described it, doesn't really work.
Plato, so the story goes, defined a human as a "featherless biped". Diogenes, so the story continues, plucked a chicken and brought it to Plato's academe, saying "here's your human". Even though Plato wasn't presenting a serious definition of human and the incident may or may not have happened at all, it's a good example of the difficulties of trying to pin down a set of properties that define something.
Let's try to define something simple and ordinary, say a house. My laptop's dictionary gives "a building for human habitation", that is, a building that people live in. Seems reasonable. Building is a good example of an abstraction. It pulls out the common properties of being built, and not movable, for people to be in, common to things like houses, office towers, stadiums, garden sheds and so on. Likewise, human is an abstraction of whatever all of us people have in common. Let's suppose we already have good definitions of those, based on their own properties (buildings being built by people, people walking on two legs and not having feathers, or whatever).
There's another abstraction in the definition that's maybe not as obvious: habitation. An office tower isn't a house because people don't generally live there. Habitation is an abstraction representing a set of behaviors, such as habitually eating and sleeping in a particular place.
The house I live in is clearly a house (no great surprise there). It's a building, and people, including myself, live in it. What about an abandoned house or one that's never been lived in? That's fine. The key point is that it was built for human habitation.
What about the US White House? It does serve as a residence for the President and family members, but it's primarily an office building. Nonetheless, "house" is right there in the name. What about the US House of Representatives, or any of a number of Houses of Parliament throughout the world? The US House not a building (the building it meets in is the US Capitol). People belong to it but don't live in it (though the spouse of a representative might dispute that). But we still refer to the US House of Representatives as a "house". In a similar way, fashion designers can have houses (House of Dior), aristocratic dynasties are called houses (House of Windsor), and so on.
You could argue that "house" has several meanings, each defined by its own properties, and that's fine, so let's stick to human habitation. Can a tent be a house? A yurt is generally considered a type of tent, and it's generally not considered a house because yurts are mobile, so they don't count as buildings. Nevertheless, the Wikipedia article on them includes a picture of "An American yurt with a deck. Permanently located in Kelleys Island State Park". The author of the caption clearly considered it a yurt. It's something built for human habitation, permanently located in a particular location. Is it a building or a tent (or both)? If it's a building, is it a building under a different sense of the word?
What about a trailer home? In theory, a trailer is mobile. In practice, most present-day trailers are brought to their site and remain there indefinitely, often without ever moving again. Though they're often referred to specifically as "trailers", I doubt it would be hard to find examples of someone saying "I was at so-and-so's house" referring to a trailer.
What about caves? I had no trouble digging up a travel blog's listing of "12 cave houses", though several of those appear to be hotels. Hotels are buildings for people to stay in, but not live in, even though some do. A hotel is also subdivided into many rooms, typically occupied by people who don't know each other. Apartments are generally not considered houses either, though a duplex or townhome (known in the UK as a "terraced house") generally is. In any case, if someone adds some walls, a door and interior design to a cave, does that make it a house? Looking at abstract properties, does this make it a building?
Is a kid's tree house a house? Is a doll house? What about a dog house or a bird house?
In a previous post, I explored the senses of the word out and argued that there wasn't any crisp definition by properties, or even a set of definitions for different senses, that covered all and only the ways we actually use the word out. I used house as an example here because I hadn't already thought about its senses and didn't know exactly where I'd end up.
Honestly, the "building for human habitation" definition held up better than I expected, but it still wasn't hard to find examples that pushed at the boundaries. In my experience, whatever concept you start with, you end up having to add more and more clauses to explain why a particular example is or isn't a house, and if you try to cover all the possibilities you no longer have a clear definition by a particular set of properties.
More likely, we have a core concept of "house", a detached building that one family lives in, and extend that concept based on similarities (a cave house is a place people live in, parts of it are built and it's not going anywhere) and metaphors (the family living in a house stands in for the house itself, an example of metonymy).
As far as I can tell, this is just how language works, and language works this way because our minds work this way. Our minds are constantly taking in a stream of sensory input and identifying objects from it, even when those objects are ill-defined, like clouds (literally nebulous) or aren't even there, like the deer I thought I saw through the snow crossing the road in hour 18 or so of a drive from California to Idaho. We classify those objects in relation to other objects, or, more accurately, other experiences from which we've identified objects.
Identifying objects is itself an exercise in abstraction, deciding that a particular set of impulses in the optic nerve is a friend's face, or that a particular set of auditory inputs is a voice, or a dog barking, or a tree falling or whatever. Recent generations of AIs which can recognize faces in photos or words in recordings of speech (much harder than it might seem) are doing the same thing. We generally think that faces and words are too specific to be abstract, but is this abstract thinking? If it is, how does it relate to examples like the ones I gave above, such as defining a species of animal?
When other animals do things like this, like a dog in the next room hearing kibble being poured into a dish or vervets responding to specific calls by acting to protect themselves from particular predators, we tend to think of it as literal thinking, not higher-level abstract thinking like we can do. Any number of experiments in the 20th century studied stimulus/response behavior and considered "the bell was rung" as a simple concrete stimulus rather than an abstraction of a large universe of possible sounds, and likewise for a behavior like pressing a button to receive a treat.
I've described two related but distinct notions of abstraction here:
- Defining concepts in terms of abstract properties like size, shape, color, how something came to be, what it's meant to be used for and so on (this species of bird is around this size with plumage of these colors, a house is a building for human habitation)
- Identifying discrete objects (in a broad sense that includes things like sounds and motions) from a continuous stream of sensory input.
The first is the usual sense of abstraction. It's something we do consciously as part of what we call reasoning. Current AIs don't do it particularly well, or in many cases at all. On the other hand, it's not clear how important it is in interacting with the world. You don't have to be able to abstractly define house in order to build one or live in it. You don't have to have a well-developed abstract theory in order to develop a new invention. The invention just has to work. Often, the theory comes along later.
Theories can be very helpful to people developing new technologies or making scientific discoveries, but they're not essential. When AlphaFold discovers how a new protein will fold, it's not using a theory of protein folding. In fact, that's its advantage, that it's not bound by any particular concept of how proteins should fold.
The second sort of abstraction is everywhere, once you think to look, so common as to be invisible. It's crucial to dealing with the real world, and it's an important part of AI, for example in turning speech into text or identifying an obstacle for a robot to go around. Since it's not conscious, we don't consider it abstraction, even if it may be a better fit for the concept of pulling out properties. Since current AIs already do this kind of abstraction, and we don't consider an AI that recognizes faces in photos to be an AGI, this sort of abstraction clearly isn't enough to make something an AGI.
There may be some better definition of abstract thought that I'm missing, but neither of the two candidates above looks like the missing piece for AGI. The first doesn't seem essential to the kind of disruption we assume an AGI would be capable of, and the second seems like basic infrastructure for anything that has to deal with the real world, AGI or not.
*That "renewed" is getting a little out of date. Sometimes considerable time passes between starting a post and actually posting it.
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