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View submission: Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science
Perhaps this is a nebulous question, but here goes: what sci-fi things* could we make for sure**, but just don't know how to, yet?
The best historical example of something like this are videocalls from the perspective of 1940-1960s-era society. Videocalls were a staple of the science fiction of the time. We had already invented television and telephones, so it was conceivable that sooner or later, we'd be able to combine the two. Lo and behold, it is 2022 and everyone has a pocket telephone, television and videocall device—all in the same box.
So, from our perspective, what is the equivalent of a video call? Something that we know with 99.97% certainty is possible, but we don't have the intermediate steps for?
I would imagine that the two obvious candidates are fusion power and AGI. Similarly, I would think that something like wormhole travel or folding spacetime to bypass the cosmic speed limit are two things which don't qualify because we don't know with a high degree of certainty that the underlying techniques are even possible. So, what else is there?
Comment by physics_defector at 17/09/2022 at 19:41 UTC*
1 upvotes, 1 direct replies
This is very much dependent on how you're defining things.
AGI is usually defined in reference to human intelligence, but it may very much be a fool's errand to attempt to replicate this outside human wetware. Which computations are efficient depends a great deal on the hardware in which they're performed. For example, there are problems which quantum computers can solve efficiently that classical/digital computers can still solve, but not efficiently[1]. In the language of computational complexity theory, this is captured by the difference between the complexity classes BQP and BPP. Respectively, bounded quantum polynomial and bounded probabilistic polynomial. Basically, both mean that if you're performing a calculation with some amount of randomness in the process (which is inherent in quantum computing), the problem can be solved on the quantum and classical (respectively) hardware efficiently.
1: https://www.scottaaronson.com/papers/bqpph.pdf
Why do I bring that up? Because it may not make sense to try to engineer human-like intelligence outside the structure for which it is optimized. So it's more useful to think of intelligence in a much more general (no connection to the "general" in AGI) sense. I don't believe there's a universally accepted definition of intelligence, but as a mathematician I think of it in terms of an agent with at least the following key features (though I may have forgotten something. A more extensive discussion can be found here[2] if desired):
2: https://arxiv.org/pdf/1902.09980.pdf
1. Using data to generate and update a set of probabilistic models each corresponding to some system or process.
2. Using these models to guide behavior in a wide (loosely defined) set of environments.
3. Said behavior including some amount of active search for information to further improve the models in a feedback loop.
To a corvid[3] - if we imagine them to have a human level of awareness - the human ability to write or use our hands may seem meaningless and trivial. By contrast, their abilities in navigation and unpowered flight would seem essential and our lack of them would seem a critical deficit. This is perhaps a silly example, but my intent is to convey that the use of "general" in AGI is very much anthropocentric. Future superintelligent AI, should they come to exist, will likely appear very, very alien to us - if not wholly incomprehensible. In fact, a tag team of mathematicians and philosophers showed that the problem of predicting the behavior of a superintelligent AI is fundamentally unsolvable. Not just practically, but unavoidably because of the mathematical nature of computation. This article[4] is a non-technical discussion of the problem, and depending on your level of interest in AGI you might really enjoy it.
4: https://jair.org/index.php/jair/article/view/12202/26642
As far as fusion, it's more a question of how efficient that power generation will turn out to be. There's probably more nuance, but I'm no plasma physicist so my understanding is limited.
But what are we confident will be feasible? The most exciting example I kow of is relatively low-velocity but commonplace travel around the solar system, along with human colonies in various locations. I say "relatively low-velocity" to distinguish the current and highly fuel-efficient but slow approach to travel within the solar system from that of hypothetical "torchships[5]". The latter would disregard launch windows and slingshots (though almost certainly not all impacts of orbital mechanics on fuel efficiency) and instead simply burn a great deal of fuel. Alternatively, once we have established a space presence as a species it could be casual, all things considered, to make use of Project Orion[6]'s extremely efficient yet high-speed means of traveling within the solar system. The historical and present difficulties are the issues of treaties against nuclear armaments in space, and more crucially the immense danger of poisoning the atmosphere on the way to orbit.
5: http://www.projectrho.com/public_html/rocket/torchships.php
6: https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)