If you explain things away with magical technology you aren't really writing sci-fi but you are writing fantasy.
What is your problem with a story where it is possible to create a second personality in your brain using technology? (let's discuss just this story idea here, but not Inception, for clarity). As far as my understanding of the issue goes, tulpas are likely using their host's mental resources in a way, so to create a second personality that is capable of independent work during host's downtime, some kind of hardware upgrade for a host's mind should be necessary.
I imagine the necessary mind upgrade should be similar to upgrading single-core CPU to single-core CPU with hyper-threading.
What is your problem with a story where it is possible to create a second personality in your brain using technology?
I think you likely ignorant about a lot of practical aspects that come up when one creates a second personality inside a person if you never talked to someone who dealt with the issue on a practical level.
I particularly don't believe in the need to have a full persona that's unaware of the host. I heard an anecdote on a hypnosis seminar about a hypnotherapist who created a secondary persona in a college student to help the student learn....
There have been a number of discussions here on LessWrong about "tulpas", but it's been scattered about with no central thread for the discussion. So I thought I would put this up here, along with a centralized list of reliable information sources, just so we all stay on the same page.
Tulpas are deliberately created "imaginary friends" which in many ways resemble separate, autonomous minds. Often, the creation of a tulpa is coupled with deliberately induced visual, auditory, and/or tactile hallucinations of the being.
Previous discussions here on LessWrong: 1 2 3
Questions that have been raised:
1. How do tulpas work?
2. Are tulpas safe, from a mental health perspective?
3. Are tulpas conscious? (may be a hard question)
4. More generally, is making a tulpa a good idea? What are they useful for?
Pertinent Links and Publications
(I will try to keep this updated if/when further sources are found)
(Bear in mind while perusing these resources that if you have serious qualms about creating a tulpa, it might not be a good idea to read creation guides too carefully; making a tulpa is easy to do and, at least for me, was hard to resist. Proceed at your own risk.)
Footnotes
1. "Conjuring Up Our Own Gods", a 14 October 2013 New York Times Op-Ed
2. "Hearing the Voice of God" by Jill Wolfson in the July/August 2013 Stanford Alumni Magazine
3. "The Illusion of Independent Agency: Do Adult Fiction Writers Experience Their Characters as Having Minds of Their Own?"; Taylor, Hodges & Kohànyi in Imagination, Cognition and Personality; 2002/2003; 22, 4
4. Thanks to pure_awesome
5. "Sentient companions predicted and modeled into existence: explaining the tulpa phenomenon" by Kaj Sotala