I have been waiting for someone to write about this for a very long time now. I started with computers as a boy with BASIC and have thought about all of these levels many times, visualizing it in my mind. I am eager to read this.

I have been waiting for someone to write about this for a very long time now. I started with computers as a boy with BASIC and have thought about all of these levels many times, visualizing it in my mind.
 
I am eager to read this.
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 “hardware and software are logically equivalent”
oh i’m loving this.
Black boxing NOT coarse graining…. oh this is good.
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 1
There are of course lower levels than the electron level, as described by the standard model of particle physics, which may in
turn depend on even lower levels such as string theory/M theory.They are of no concern to us here.
I’m actually grinning as I read this. I don’t feel ‘glee’ much but I’m stopping and applauding as I read. Hits the nail RIGHT with each sentence.
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I’m actually grinning as I read this. I don’t feel ‘glee’ much but I’m stopping and applauding as I read. Hits the nail RIGHT with each sentence.
 
Waited so long for SOMEONE to get this right.
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“Overall there is no continuous derivation of the relevant properties from the Hamiltonian .
 
There are rather a series of empirically adequate phenomenological models building on each other but not derivable from them.”
 
The shells. Ahhh. the shells. It is not continuous. Not… Continuous.
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F’in YES
 
“The so-called derivations of the results of solid state physics from microscopic principles alone are almost all bogus,” [Leggett (1992)],
 
THANK YOU Leggett 1992.
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 software + hardware are logically equiv. I know.
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lvls1 lvls2 lvls3
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 key is: black boxing NOT coarse graining. You can’t just go from bottom up. With digital computers, it’s downward causation.
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 This is specifically interesting to me because: “it’s all just electrons” or “it’s all waves rippling up” isn’t always the case and certainly not with computers.
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Oh it’s as if every 5th sentence is gold.“Logical: A computer program as a whole [Abelson and Sussman (1990)] is an irreducible higher level entity”That ONE thing is SO damn difficult to explain to people. They think it can be logically broken up but if you do, IT WON’T COMPILE.If it doesn’t compile, IT’S NOT A PROGRAM.A program is a logical entity of itself. It only achieves this status when it successfully compiles.It is as close to magic as I know.
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This paper is putting into writing what I’ve been playing around with in my head since I was about 12 yrs old and wrote my first BASIC program and read “getting started in computers” and stuff.
 
…and it’s getting EVERYTHING correct. So, this is a particular, specific glee for me. I have never read anything so thoroughly correct to my understanding that goes to these levels of reality and technology.
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“The logical-physical interface
 
Logical variables – which are defined in digital computers at each level of the virtual machine hierarchy cannot be derived from physical variables because they are simply of a completely different nature. Rather they can be represented by physical variables – which cannot possibly be a bottom-up process, because the very concept of logical variables is not a physics concept.”
 
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“Computational processes are abstract beings that inhabit computers. As they evolve, processes manipulate other abstract things called data. The evolution of a process is directed by a pattern of rules called a program. In effect, we conjure spirits of the computer with our spells. A computational process is indeed much like a sorcerer’s idea of a spirit. It cannot be seen or touched. It is not composed of matter at all. However it is very real. It can perform intellectual work. It can answer questions. It can affect the world by disbursing money at a bank or by controlling a robot arm in a factory”.([Abelson and Sussman (1990)]As quoted in: “How Downwards Causation Occurs in Digital Computers”, George Ellis, 2019
 Magic. All this time working with it and I have always been in awe of this magic. And, it is.
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 Abstract entities have causal powers
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  This equal effectiveness of all higher levels is the explicit result of a largely uncelebrated aspect of computers: the devel- opment of compilers and interpreters that translate logic representations downwards between levels [Aho et al (2006)], without which computers would be largely unusable. 2 This is the explicit machinery that acts downward to enable abstract high level programs to control ?ows of electrons in transistors in such a way as to represent abstract logic. In physics terms, the logic of the relevant algorithm is represented by the time dependent pattern of change of the potential energy term (7) in the electron Hamiltonian, in accord with the digital representation of the algorithm in machine code.
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Thank you George Ellis. I’ve never enjoyed reading a paper so much as this one.
 
There is tremendous difficulty in explaining to those who don’t know how computers function down “to the metal” how computers do NOT prove that the universe is logic, or the universe is math, or that physics rules all, but INSTEAD that computers are realizations of our free will, of our intentions manifest in machines — that it is WE who are controlling the logic and physics in computers and not the logic and physics controlling us.
 
Grains of sand do not pull a shovel into them so that they move into a sandcastle. Arguably, grains of sand have the affordances to do so but such an upwards trek without downward constraints and no one to appreciate the aesthetic makes it unlikely.
 
Who would be the Grace Hopper to lead us to the sand castle? A child, complex being, with a shovel in hand and layers of abstraction affording downward causation, a first compiler of sand.
 
How Downwards Causation Occurs in Digital Computers
George Ellis
https://philarchive.org/rec/ELLHDC-2
grac
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 Complicated. But humans pushing levers that push grains of sand to do stuff quickly.
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 You can imagine tiny hamsters behind every part of a computer. I do that sometimes.
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 I got ridiculously poetic here but as a lifelong computer geek, reading an ACCURATE description of computer functionality down to the Hamiltonian is gorgeous.
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 It’s not. “You can’t get there from here”
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 As a lifelong computer nerd _and_ physics buff, I’ll vouch for this whole paper, every word.
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Causation is DOWNWARDS in computers.
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 MAYBE, but causation will still be downwards. Who builds the machinery?
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 You can run in parallel. But flow is still going down layers of abstraction, even if we allow for lateral movement within layers. and feedback to higher levels.Look at quantum computing. We allow more degrees of freedom and “listen”. But it is still downward causation, just more respectful.

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 Oh, I’m not going into a religious thing with all this :) Just sticking with computers…. mostly… oh, and free will.
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