[tsimionescu]

I've never understood why certain philosophers view computation as some kind of abstract symbolic manipulation, while they easily accept that consciousness is a physical process.

Computation is something that a computer provably does. We build physical hardware, at great effort, to do computation. The hardware works and does the computation regardless of whether there is anyone to understand or interpret it. If it didn't, we couldn't have built anything like, say, an automatic door: that is a form of computation that provably happens as a physical process that is completely observer-independent.

Sure, a different entity than a human might view it completely differently than a door opening when someone is near - but the measurable physical effect would be the exact same, with the exact same change in momentum and position of the atoms in what we call the door based on the relative position of some other atoms and the sensor.

[Tryk]

>Computation is something that a computer provably does.

This is a circular definition. In order to properly define the concept, we must be able to word it without using "computing devices" in the definition.

Finding a satisfactory definition for what constitutes a "Computation" is actually an interesting debate goes back to the 1600s. Currently, the mainstream definition (from wikipedia) gives that: "A computation is any type of arithmetic or non-arithmetic calculation that is well-defined".

One way to understand the author is to learn more about the "The mapping account" theory behind computation: "a physical system can be said to perform a specific computation when there is a mapping between the state of that system and the computation such that the 'microphysical states [of the system] mirror the state transitions between the computational states.'"

[tsimionescu]

I wasn't trying to use that as a definition of what computation means. My point is that regardless of how we define it, the fact is that the devices we build to do some form of computation are objectively successful at doing what they were built to do.

For example, you can say that Firefox is a human-centric abstraction, and that my computer isn't running Firefox right now in an objective sense, that this is is just a human-centric interpretation of what the physical device is doing, and that there exist other computations that we could assign to it.

But what you can't say is that the device is not affecting the physical world in ways that are consistent with performing the Firefox computation, such as causing certain specific wavelengths of light to be emitted by the screen based on state that is stored in a server in the YCombinator data center. This is a measurable fact of the physical world that is independent of the model of computation you chose to ascribe to the physical device - any consistent mapping will have to preserve this same physical property.

[bch8_]

The paper addresses this point in section 3.2. They aren't debating the fact that a physical process is taking place in a computer running a program. They are arguing that the semantic interpretation of the output of that program is indeterminate and dependent on the mapping function:

> A single physical vehicle (bottom) possesses a fixed causal trajectory. However, it does not instantiate a unique computation. Depending on the alphabetization key applied (fA or fB ), the same physical states can be mapped to entirely different abstract computations (Top Left vs. Top Right). Therefore, computation cannot be intrinsic to the physics (p).

So yes there is a physical process generating your Firefox browser, but there is also a mapping function taking that program and interpreting that it should display your Firefox browser. There are any number of mapping functions that could be applied to the physical state in order to display other things on your screen besides the browser. Therefore, the Firefox browser being displayed is not inherent or intrinsic to the physical state of your computer. If we did not have the right mapping function, we would have no way of knowing or inferring or discovering which mapping function is correct.

[tsimionescu]

But the results that the computer screen shows, and the inputs fed into the machine, are entirely physical, observer-independent processes. Just like an inscribed papyrus contains letters in a physically observable, provable sense - even if the semantics of those letters are entirely man made.

This is in fact very similar to the notion of text - text is a physical medium, that provably contains a message that one human intended to convey to other humans. The same physical text can be interpreted in an infinite number of ways, and they are all equally valid in that they are self-consistent, but only one is the intention of the original author.

[bch8_]

To the best of my understanding I believe the response from the position taken by the paper is that this is still committing the abstraction fallacy (Assuming you aren't just agreeing with them here, which I don't think you are). The book itself doesn't physically instantiate the information it contains in its text. In a vacuum it is informationally inert. That doesn't mean it doesn't physically exist. Likewise the computer running Firefox obviously physically exists. The fallacy is the next jump from there - assuming that the semantic content of the book or software is physically present in those items. Another example given in the article is an analog clock:

> Consider an analog clock. Physically, the device is a collection of gears and springs governed by continuous dynamics (P). It only “computes” time because a mapmaker intervenes, mapping a specific set of continuous angles to a semantic concept (e.g., “3:00 PM”). Without this semantic imposition, the clock is just metal moving in accordance with Hamilton’s equations; it contains no intrinsic “time.” Thus, the physical substrate does not “process information” absent a prerequisite alphabet of intrinsic symbols; rather, it generates continuous dynamics that an external mapmaker interprets as information.

In this example the time "3:00 PM" is instantiated in the mind of the person reading the clock, it is not a real physical property of the clock itself.

[tsimionescu]

I think the book example muddied the waters, unfortunately. I agree that the concept "3:00 PM" only exists in the mind of the observer. But I don't agree that this means the clock's mechanism isn't intrinsically, objectively, a time keeping mechanism. The clock is a physical instantiation of a time keeping algorithm, in an objective sense. The meaning of a particular time, or even the interpretation of time, is a subjective human experience, but that doesn't mean that computation is as well. If the clock wasn't a correct instantiation of the time keeping computation, it wouldn't be possible to interpret it as such, it wouldn't work - that's what makes me believe it's more than semantics.

[Teever]

If this mechanical clock mechanism was part of some sort of Von Neumann probe that was sitting dormant in a star system waiting for the clock to strike a specific time and when that occurs it triggers another mechanism in the probe that combines stored nucleotides to produce a particular sequence of RNA and DNA that is seeded into a suitable world and that soup of RNA and DNA eventually evolves into intelligent biological life that finds the Von Neumann probe and learns to interpret the symbols and purpose of the probe and comes to understand what 3:00 PM means, does that whole system have the real physical property of 3:00 PM in it?

[gwd]

> I've never understood why certain philosophers view computation as some kind of abstract symbolic manipulation

Possibly very early AI misled people here. In the 80's, a huge amount of AI was logic manipulation; "If A then B is valid"; "A is true"; therefore, "B is true". It's not hard to see how people would conclude that that sort of symbolic manipulation could never result in consciousness.

But modern neural nets aren't like that at all. Calling modern neural nets "symbolic manipulation" seems insane; like calling libraries forests, and insisting we can apply scientific principles about forests to them, because books are made of trees.

[twosdai]

Really great point. I have wondered that as well.

Even weirder to me is that in the case of a person doing the computation on a board or paper or whatever medium, its still computation. This time the physical medium doing the work, is the human and their brain.

If consciousness can be proven to emerge from computation alone, then in a way we humans with our brains can simulate a new consciousness.

[Maxatar]

>I've never understood why certain philosophers view computation as some kind of abstract symbolic manipulation

The abstraction is over the multitude of different physical ways that computation can be performed. That is the role of abstraction, to separate something from a particular means of implementation so that we can think about computation without having to fix a particular physical process.

[tsimionescu]

Sure, but I don't think that's what this paper and other similar ones are saying. I agree, of course, that things like programming languages or algorithms or even logical circuit diagrams are abstractions, obviously. But they are abstract descriptions of a real physical process that happens, for example, inside a CPU - in exactly the same way that an electrical diagram is an abstract descriptio of a real physical process that happens in an electrical circuit, or a thermodynamic calculation is a description of what happens inside an engine.

But the engine, the electrical circuit, and the computation inside the CPU are objective realities. There could be many other ways to describe and characterize the same physical realities, of course, but that doesn't make them observer-dependent phenomena.

[cameldrv]

The issue that the paper brings up is that the same physical process can be interpreted as multiple different computational processes. If the content of consciousness (the hard problem, qualia) is only dependent on the computational process, and not its particular physical instantiation, then which qualia are generated from a particular physical process?

[tsimionescu]

> The issue that the paper brings up is that the same physical process can be interpreted as multiple different computational processes.

I don't think this is relevant to the notion that consciousness is a form of computation.

The assertion that consciousness is a form of computation basically means that the physical process that happens in the brain/body that we recognize as consciousness can be described in terms of a computational process. A consequence of this, if it is true, is that replicating the same computation in a CPU would make the physical process that happens in the CPU just as conscious - assuming that we had identified the correct computation.

In this theory, the thing that would be conscious would be the physical CPU, just like the thing that is conscious is a physical human brain/body. The computation is just an abstract description of the common properties between the CPU and the human brain/body. It's not relevant that we could also describe the process inside the CPU as being a completely different computation - the abstract model is only required to be able to build and program the CPU.

To go back to my mechanical door analogy: we create an abstract model of the computations needed to make a computational system open a door when a person is near. We use this model to create the computational system, and we see the door opening when a person goes near the sensor. Now, we can interpret the computation happening inside the system in many other ways - but that won't change the fact that the door opens when a person is near, in any way.

I am not claiming that any of this constitutes proof that consciousness must be a computation. What I'm claiming though is that the paper, and similar arguments, are not refuting the right claims, and generally have a misunderstanding of what "computation" actually means, and its relation to physical processes.

[cameldrv]

The "hard problem" is talking about the thing that it's like to be you, to experience what is happening. I don't know about you, but I only experience one set of things happening at once, i.e. it doesn't feel like I am in two places at once or that there are two completely different versions of my life happening simultaneously.

If the physical thing that is conscious is the CPU, what are the contents of its consciousness if there are multiple interpretations of what it is computing?

Now maybe somehow there are in fact multiple consciousnesses inhabiting the CPU. I don't experience that though, so I don't have a positive reason to believe that that's true.

[tsimionescu]

You are presupposing that there is a single way an outside observer could interpret the way your brain works to produce consciousness. I don't see why we should believe this. The same way, even though we can model the processes in the CPU as multiple computations, perhaps only one of these models is correct in some way, and that is the model we call consciousness. Of course, this becomes highly speculative.

[wdbm]

Why assume there has to be a one-to-one mapping? Why assume one physical process can't correspond to an infinity of different qualia?

We assume an infinity of wave-functions correspond to a single physical process without difficulty.