It has come to my attention that esper power, arguably the most used and shown supernatural power in the series (in that most of the action take place in Academy City, and there are the two spin offs), is actually still in the vague on many parts. We supposedly have the mechanics, but not in full, and the backstory is sketched at best. Here is a rundown of the unknowns of power development of which we haven't received a full explanation:
- According to Tsukuyomi Komoe, Level 0s are an anomaly, since the Power Curriculum Program can theoretically allow people to gain their own personal reality, and therefore powers if they consume enough "curriculum". So why do they exist, and why are they the majority of esper population?
- The Power Curriculum Program can apparently only be done on children, as hinted at by Misaka's mom saying that she can't enter the program because of her age in SS2 (“Hmm. That does sound like fun, but someone my age can’t take part in the Curriculum that develops psychic powers”), and also before their puberty as stated in NT11 (We must make the decision before they enter the harsh hormone fluctuations of adolescence to ensure their talent is not crushed). Beyond that, no complete explanation on why it is so.
- In OT8, it is said that AC couldn’t find any plants and animals other than humans able to develop esper powers. Musujime wanted to find out if specially intelligent animals could develop esper powers or if they were exclusive to humans for some unknown reason. No answer on whether she was right or not.
- Gemstones, the "natural" espers, are just as mysterious, if not more. A phenomenon older than AC, and presumably as old as the existence of magic, and, beyond the speculation of the PPC being reproduced naturally, it is still vague as the means are unknown, as well as the why. The explicitely labelled Gemstone powers shown in the series are outright weird compared to the AC produced versions, with two of them not even looking scientific. Maybe the Power of the World is somewhat involved.
- The new plot point brought up in NT11: (*Important Note: This point holds the possibility of overturning the fundamental idea of researching the brain to develop esper powers. The brain is a necessary component, but there may be more than just that. I hope you treat this part especially carefully.) Esper powers apparently originate further than the brain. This was actually lampshaded earlier in NT5 (However, Academy City psychic powers are not controlled with just the brain. The entire physical body controls them.) and in NT7: (Rensa could theoretically use any esper power, but she was really only using her ability as a cyborg to create an output point for the power. As she was only borrowing the power, a power would forever disappear from her stock if the original owner die). If the source for esper powers was only the brain, and Rensa can rearrange her brain and body to recreate other esper's, why would she just be able to act as an output point and stop being able to use a power if the owner dies but she still has their data?
Are there other unresolved questions on esper powers?