Maybe it’s a life-long diet of science fiction, but I seem to have written some trilogy posts lately. This post completes yet another, being the third of a triplet exploring the differences between physical objects and numeric models of those objects. [See Magnitudes vs Numbers and Real vs Simulated for the first two in the series.]
The motivation for the series is to argue against a common assertion of computationalism that numeric models are quintessentially the same as what they model. Note that these posts do not argue against computationalism, but against the argument conflating physical and numeric systems.
In fact, this distinction doesn’t argue against computationalism at all!
Indulging in another round of the old computationalism debate reminded me of a post I’ve been meaning to write since my Blog Anniversary this past July. The debate involves a central question: Can the human mind be numerically simulated? (A more subtle question asks: Is the human mind algorithmic?)
An argument against is the assertion, “Simulated water isn’t wet,” which makes the point that numeric simulations are abstractions with no physical effects. A common counter is that simulations run on physical systems, so the argument is invalid.
Which makes no sense to me; here’s why…
Over the past few weeks we’ve explored background topics regarding calculation, code, and computers. That led to an exploration of software models — in particular a software model of the human brain.
The underlying question all along is whether a software model of a brain — in contrast to a physical model — can be conscious. A related, but separate, question is whether some algorithm (aka Turing Machine) functionally reproduces human consciousness without regard to the brain’s physical structure.
Now we focus on why a software model isn’t what it models!
Last time I introduced four levels of possibility regarding how mind is related to brain. Behind Door #1 is a Holy Grail of AI research, a fully algorithmic implementation of a human mind. Behind Door #4 is an ineffable metaphysical mind no machine can duplicate.
The two doors between lead to physical models that recapitulate the structure of the human brain. Behind Door #3 is the biology of the brain, a model we know creates mind. Behind Door #2 is the network of the brain, which we presume encodes the mind regardless of its physical construction.
This time we’ll look more closely at some distinguishing details.
The ultimate goal is a consideration of how to create a working model of the human mind using a computer. Since no one knows how to do that yet (or if it’s even possible to do), there’s a lot of guesswork involved, and our best result can only be a very rough estimate. Perhaps all we can really do is figure out some minimal requirements.
Given the difficulty we’ll start with some simpler software models. In particular, we’ll look at (perhaps seeming oddity of) using a computer to model a computer (possibly even itself).
The goal today is to understand what a software model is and does.