On the contrary, computation is a very clear physical phenomenon, well understood and studied, so well understood that we can build machines to do it. And, again, those machines don't need any interpretation - they do measurable things in the real world, such as opening doors and cutting parts.

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mjburgess 3 hours ago | parent [-]

I have never encountered this physical process. Here I am typing on a keyboard which is powered through an electrical field that is guided by a peice of wire under each key -- whose operation, when mechanically activated, is to induce some electrical state in some switches it is connected to, and so on.

I associate the key with "K", and my screen displays a "K" shape when it is pressed -- but there is no "K", this is all in my head. Just as much as when I go to the cinema and see people on the screen: there are no people.

By ascribing a computational description to a series of electrical devices (whose operation distributes power, etc.) I can use this system to augment by own thinking. Absent the devices, the power distribution, their particular casual relationships to each other, there is no computer.

The computational description is an observer-relative attribution to a system; there are no "physical" properties which are computational. All physical properties concern spatio-temporal bodies and their motion.

The real dualism is to suppose there are such non-spatio-temporal "process". The whole system called a "computer" is an engineered electrical device whose construction has been designed to achive this illusion.

Likewise I can describe the solar system as a computational process, just discretize orbits and give their transition in a while(true) loop. That very same algorithm describes almost everything.

Physical processes are never "essentially" computational; this is just a way of specifying some highly superficial feature which allows us to ignore their causal properties. Its mostly a useful description when building systems, ie., an engineering fiction.

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jhickok an hour ago | parent | next [-]

Right, and I seem to remember this sort of point in Wittgenstein as well in his rule-following argument where, to make an adjustment to his question, what would it mean for a computer to be miscomputing other than bucking our expectations for what a system should produce; all computers clearly are performing exactly as our physics describe them, even if they produce 2 * 2 = 5 on a screen.

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tsimionescu an hour ago | parent | prev [-]

And yet you can build a device with the exact same functionality using vacuum tubes, semiconductor transistors, field effect transistors, water pipes, ant molehills, and any other substrate - and you could even replace some of the components with a software-defined hardware component that does the same thing. The computation is the thing that is objectively the same between all of these different realizations of the same device - the software that they are running. And for many of these, the software is indeed a physical object, one whose presence you can precisely measure. A hard disk containing a copy of quicksort has different physical properties that the same hard-disk containing a copy of Windows. A CPU currently running quicksort is likewise different from a CPU currently running ChatGPT, in perfectly measurable and observable ways.

A computational description of a system is no more and no less rigurous than any other physical model of that system. To the same extent that you can say that billiards balls interact by colliding with each other and the table, you can say that a processor is computing some function by flipping currents through transistors.

	▲	mjburgess an hour ago \| parent [-]
		> software-defined hardware component that does the same thing No, you cannot. A hard-drive needs to a have a physical hysteresis. An input/output device needs to transmit power, and be powered, by an electrical field. A visual device needs to emit light on electrical stimulation, and so on. The only sense, in the end, in which a "computer" survives its devices being changed is just observer-relative. You attribute a "3" to one state and a "1" to another, and "addition" to some process. By your attribution, does that process compute "4". But it computes everything and computes nothing. If you plug in a speaker to VGA socket, the electrical signal causes an the air to move, sound. The only sense in which a VGA signal is a "visual" signal is that we attach an LCD to that socket, and we interpret the light from the LCD semantically. The world is a particular way objects in space and time move, those exhaust all physical properties. Any other properties are non-physical, which is why this kind of computationalism is really dualism. You suppose it isnt your physical mechanism and its relationship to your environment which constitutes your thinking -- rather it's your soul. A pure abstract pattern which needs no devices with no specific properties to be realised. Whatever this pattern is, if you played it through a speaker, it would just be vibrations in the air. Sent to an LCD, whitenoise. Only realised in your specific biology is it any kind of thinking at all.