You seem to be asking, essentially, how new ideas are formed, and whether computers can have independent creativity.
I'm a bit more specific, It's not as general as "how idea are formed", I'm past the point of asking what creativity is, generally accepting that creativity lies in a spectrum inside a triangle define by order, chaos and purpose (or fitness) and have different degree of complexity (the question being less about can computer have independent creativity but at which complexity or what kind).
I'm specifically asking for a brand of "creativity", called "assumptions". Creativity in computer is attacked from two angles:
1. Let the computer form "intent"
2. Manipulate structure
"Assumption" would be in the middle.
For example Angelina is brilliant (if we let the complexity scale outside), it let the system have an "experience" (scouring the web), form ideas and turn them into intent, then this intent is fed to a structure as constrains to create a structured composition.
However while Angelia is expressive and have some form of creativity, it just feed a system of game creation without reflecting on it like it does for web data, it does not experience its own creation, but for human the creativity is often very iterative. As a procedural generation system, it's "exploitative" (vs "exploitative") as the exploration is emulate by the "randomness" of the experience of web site. The metaphor module being an additional "filter" and constrain to match human expectation of creativity.
Which also beg the question of independent creativity not just for machine but also human, are we that independent when our output is dependent on our experience too? But I see no evidence of the computer system (angelina) learning from previous experience to produce new experience, I don't think it's a requirement, just a problem of complexity scale, it does not invalidate the computer's experience.
To fight this exploitative assumption Angelina has a module of level design and movement evolved through GA, it's exploratory (as in trial and error), the fitness function being conceptually a simple way to experience the design (complexity left out but conceptually the same). However the fitness function itself is fixed and made of assumptions in the domain of the problem (it will only generate space traversal design which is the main design assumption).
A lot of experience designer handwave procedural generation because, when they look at them formally, they see the fixed assumption first, it's what matter to them not the simple permutation or fitness. For the same reason they see value in procgen as saving time when presenting as "tools".
They are quick to point that the output is samey and get bored because they recognize the same assumption applied all along. Generally the best generator implement system that vary assumption based on random input from a higher hierarchy (biomes as example) within a lower frequency but even that has limits, the same don't create new assumptions. They say that it cannot match human creativity pointing at work of great artist.
To contrast is that people interested in procedural generation as creativity are just fine with the infinite minute permutation. They tend to draw attention to meaningless big number (18 quitillions planet) and amazed by unexpected collision of property, effectively treating the simulation as a complex Rorschach test. They don't get why other people handwave it so easily, pointing that if it doesn't match human creativity, most human don't match that ideal too, showing the mass of clone and soulless rip off that always inundate the market, sure an algorithm can match that with consistent quality.
Most of the process of creativity for veteran, aside from applying what is learned, is to know where the assumption need to be broken to achieve the desired expression (How do I do that, aka exploitation) or challenge them to see if they lead to valid new experiences (Why do I do that, aka exploration). Ie they class problem as such:
1. The problem is known the solution is known (applying)
2. The problem is known the solution is unknown (solving)
3. The problem is unknown the solution is unknown (creating)
It's just moving the creativity problem up the complexity chain, 1 is typical generator, 2 is exploitative generator such as the level design of Angelina. 3 would be closer to my concept of "assumption" and closer to "why do I do that".
For example what if Angelina could not only experience web page, but also its own output and modify his own code to match better the combined experience of the exterior world and internal world? How could this be even possible?
The question being is there works that explore this particular question set of creativity? And is there a possibility for a machine to understand and create assumption based on its experience of the creative process and challenge it? Is there a conceptual framework (even on the low complexity scale) that mimic those concept? Is there a set of all assumption we can translate into a universal language of procedural generation? Will Angelina win Brad over Jennifer?