My last post
inspired a good bit of conversation in the comments, nearly all of which thought the argument that we might all be in a simulation was pretty much bunk.
The argument itself held that either we are very likely to be in a simulation, or one of the following is not true:
- It is possible to have human intelligence without a brain by simulating a brain computationally
- Humanity will eventually develop the computational resources to easily simulate Earth's history at least through the present and near future
- Posthumans with access to the requisite computational power will never choose to run such a simulation
Interestingly, nobody argued with point 1. Apparently everyone agrees that you don't need a meat brain to have intelligence.
Several people objected to 2. The first objection seems to be that you can't simulate the history of humanity without simulating the history of the entire universe, which is computationally infeasible.
This seems so obviously untrue to me that I wonder if I'm misunderstanding the point. Your simulator needs to simulate the mental states of every human it cares about, plus all the sensory input those humans have... and that's it. For consistency's sake you probably need to keep a fairly detailed model of the things that people are likely to interact with, but you don't need to track the paths of every electron unless someone is setting up a cloud chamber.
Our sensory bandwidth is really low, and if you can model the mental states of a person completely, you presumably know what they are looking at and investigating. You don't really need to simulate the molecular behavior at the center of Jupiter until someone starts an experiment that looks at it -- something simpler that looks reasonable is all you need for the vast majority of the simulation.
The second objection seems to be that we may not ever get large enough computers to simulate even one person. It's true that Moore's law can't hold forever, since there's a physical upper limit to computation in the universe; presumably we'll hit the Moore's law wall well before then. However, we don't need exponential increases in computing power to get to the really impressive resources needed for whole-world simulations, we just need a lot of time plus any growth at all. I have no doubt that we'll have enough power to easily do such a thing if we want to, assuming society doesn't collapse before we get there.
Also brought up at least twice was that the programmers wouldn't be good enough to get such a simulation right. This is possible, I suppose, but we're very very early in the history and development of programming languages, and we can already do pretty amazing things. There's going to be a lot of progress between now and the postulated future of big chunks of computronium
The most interesting objections came to point 3, though nobody made what I thought was the most basic observation about post-humans: by definition, we have no idea what they will or won't want to do. Maybe they won't be interested in historical simulations (or alternate world simulations) for reasons that wouldn't be obvious to us. If your greatest ambition is to keep the fire lit in your cave, or to find the secret of bronze that your enemies are using to drive your tribe away, are you equipped to understand the deflation of the credit bubble
, or why people are simultaneously enthralled and disgusted at one man's ability to hit a ball with a stick
, really hard. It's just unreasonable to try to predict what a post-human might want or not want to do.
Having said that, some of the objections are pretty questionable.Will humans really evolve to the point that they would be willing to expend ludicrous amounts of resources just to achieve what is basically the ultimate game of SimCity... for the hell of it?
It shouldn't take much effort to come up with interesting research goals that could be evaluated with complete simulations. It's a much more plausible way for a future Hari Seldon to validate psychohistory
, for instance. Really anyone interested in history, economics, political science, etc., should be interested in historical models. Unless, of course, those fields have been completely mined out by the time we have the resources to fully model human history.
Anyway, all that's required for the sim argument is for some researcher or hobbyist to take it up, for any reason at all. I can think of a lot of arguments why no particular group or individual would simulate history, but to claim that no member of humanity will ever do, well, anything, seems like a bit of a stretch. The arguments against computation are much more persuasive than the arguments against future behavior of post-humans.
My favorite comment
comes from an anonymous poster (not Ming, the usual suspect) who posted a couple small comments, then the next day came back with this:As written before, the universe can be seen as a quantum computer calculating every possibility simultaneously real time. The universe as we know it is a personal time bound interpretation of an approximate outcome of infinite (time)local calculations. The global universe as we know it is derived from cultural classifications of perceptions, shaped by interpretations within basic human experiences, and when science is involved ruled/written out by/in abstract mandatory formulas.
...The next 30 to 50 years will be fussy. We'll need to adapt to complete new concepts of reality which will turn our lives upside down. We will see severe clashes between old world perceptions like religions and new insights which are proved by then everyday technology. Beyond that we will find ourselves in a supercultivated hyperfriendly universe in which human nature matches exactly with nature. And yes, probably we'll meet neighbours too. It's way too quiet out there, even if all clever species blew themselves up.
I definitely don't agree with all of this -- for one thing, I think the universe is a fundamentally inhospitable place, and the next 50 years isn't going to change that. But his (or her) basic point stands: the future is a very very strange place. Our current ideas about reality are going to be rethought and turned around, only to require rethinking again. Quantum computation
will rewrite everything we know about computers, and then nanotechnology will change everything we know about materials. In only a few decades, there will be more computational power in silicon than in the skulls of humanity -- unless we go into intelligence amplification
, which is an even surer route to post-humanity.
The future, even the near future, will be more different from the present than the present is from the dawn of the industrial revolution. Happy landing, indeed.