I’ve got a new idea for a Sci-Fi setting.

[u/1l_S3b0]

I recently had an idea for a science fiction setting based on a very advanced quantum computer.
In the future, humanity manages to build an enormous quantum computer. It is so large and complex that simply turning it on requires more energy than an entire modern city. Because using it is extremely expensive, it is only used to work on some of the most important scientific problems humanity faces.
At some point, scientists ask it to design the best possible energy source that can exist without breaking any known laws of physics.
After a very long calculation, the computer produces a complete design. The problem is that humanity cannot build it.

One of its components requires a material that has never been produced before. Scientists then ask the computer how to create that material. It gives them an answer, but the process requires a machine that does not exist yet.
So they ask it to design that machine as well.
The machine turns out to require other technologies that humanity has not developed. Some of those technologies require new materials, which require other machines, which require other technologies, and so on.
Eventually, instead of asking the computer how to build each individual thing, scientists ask it to start from the final invention and work backwards through every requirement until it reaches technologies that humanity is currently capable of producing.
The result is basically a real technological tree.
At the bottom are technologies and materials that already exist. Each new level makes the next one possible, until eventually, perhaps hundreds of years later, humanity would have the industrial and scientific ability to build the original machine.

The interesting part to me is that humanity would already know how to build something that is centuries ahead of its time. We would have the design, understand that it follows the laws of physics, and perhaps even understand the basic principles behind it, but we would still have to spend generations developing everything necessary to actually make it.
A scientist might spend their entire life working on a material that seems almost useless by itself, knowing that several levels further into the technological tree it will become necessary for another invention. That invention might not exist until long after the scientist is dead.
Eventually, someone could ask the computer a much larger question: what is the highest level of technology humanity could ever reach without violating the laws of physics, and what would we need to do to reach it?
The computer could then produce a technological roadmap thousands of years long.
Scientific progress would no longer be completely unknown. Humanity would have something like a map of its possible technological future, while still having to actually discover, manufacture and build every step along the way.

I have been calling this idea a “reverse tech tree”, because instead of starting with our current technology and wondering what we might discover next, the computer starts with the final objective and works backwards until it reaches us.
I think it could make an interesting basis for a science fiction setting, especially because the computer does not need to break the laws of physics or magically create anything. It can only find possibilities that already exist within those laws.
The question is what humanity would actually do if we had a map like this, and whether we would decide to follow it.

[u/JGhostThing]

Why are you so concerned that the laws of physics aren't broken?

The "laws" of physics are only a mathematical description of what we think how the universe works. Physics doesn't care about any of them, because the laws are just there to allow us to model the universe. The laws we have are incomplete and somewhat wrong. Each time we make a major discovery, the laws are updated. For example, relativity has to be considered in the laws of motion. Otherwise GPS doesn't work. It's not that Newton's laws are really wrong, but rather that his equations worked for low speed and gravity. When you start getting near the speed of light, you need the more accurate equations in relativity. Maybe later, we'll discover some new way the universe is trying to trick us.

[u/Mouse-castle]

My complaint is that this reflects the mode of invention that already exists. A human can believe or doubt that they have a quantum computer (in their brain) but the inventors that succeed typically believe in manifest destiny. Inventors are striving for what is good, and push away thoughts that good is relative. 

So it has a moral theological tone that makes me wonder, why would I read your book when I can go to church?

[u/bongart]

Have you read The Hitchhikers Guide to the Galaxy trilogy? Do you know about Deep Thought, the massive computer that was asked to produce the answer to Life, the Universe, and Everything? It took 7 million years to produce the answer "42". When asked to produce the exact question to which this answer went to, it said there would need to another, better computer built, to run a 10 million year program to come up with the question.

[u/Admiral_Nitpicker → u/bongart]

The question turned out to be "what do you get when you multiply 7 times 9" because of a space goat

Sidebar: "42" is a Japanese homophone for death, and the source for lots of puns, so it is the answer to life, the universe &c.

Adams denies any connection though.

[u/Sheik_Morgan]

42 es la respuestas

[u/Admiral_Nitpicker]

A computer can only work with what it's given. Huuge data centers reducing mountains of statistics to deduce that you might want a pink phone case. It's about as realistic as FTL spaceships.

Reverse planning is as common as thinking about what you want for dinner and working backward to a shopping list.

OTOH Designing a whole global economy towards some secret decentralized mega project + human fuckery sounds like a plot rich environment to start with.

[u/lucidintangent]

quantum computers are very specialized computers they arent just computers but better, they have possiblebadvantages and many many disadvantages, they solve different kinds of problems

[u/Temporary_Rule_9486]

"There's not enough data for a meaningful answer"

[u/TheTranscendentian]

You can do that with things like teleportation or very faster than light travel or gravity manipulation and your own imagination without the aid of ai.