I propose that there exists an active mental state in which one is emotionally neutral (i.e. no emotional valence) toward any possible outcome -- removal of access to entertainment, pleasure, one's relationships, even your own death.

I don't claim that this mental state is "better" or that anyone should try to achieve it, but experiencing it does tend to disrupt beliefs about what is necessary and important in life. Evidence suggests that desires and pleasures and entertainment and social comforts and ways to unwind that previously felt reasonably harmless and natural start to feel irrelevant and unimportant.

As far as I can tell, most of the written evidence is from the spiritual perspective, which is not always the most intellectually rigorous perspective. For a more scientific treatment of the underlying neuroscience, I'd recommend Thomas Metzinger's work; "The Ego Tunnel" is a good start. My experience is that understanding the physiological mechanisms behind our awareness, cognition, and emotion gives us a better map of how we might engineer different mental states, some of which have significant overlap with historically desirable mental states.

Metzinger proposes that our conception of "self" is basically an illusion that our brain generates in specific ways for specific purposes. Conceptually experimenting with "if this was true, what would it imply?" seems to lead to a world in which no one and no event can hurt "me", because in a way of speaking, there is no "me". Then backing down the ladder of abstraction, if I really, truly believed this, but of course still had the brain-generated perception of self, what would it imply for my everyday behavior?

The result seems to be sparser but deeper and more meaningful relationships (including with myself), much less interest in mindless entertainment and distraction, and intensified curiosity about the natural world. To the point where spending "all your free time on a hard chair with pen and paper studying" actually seems like a good idea.

Thanks for your comment. I've got Metzinger's book on my shelf so thanks for the reminder to read it :).

I must admit I have similar ideas about the self, I am currently inclined to believe that it is indeed an illusion but have not thought about the implications of that illusion (I have peace with it though).

I'm a bit more nuanced towards the emotional side. I think we all have emotions but being able to perceive them as just that, gives us true freedom. There are people that chase the emotional state/high of being happy above your normal baseline/hormonal levels, as the emotional state they want to have continuously. True freedom however comes with accepting all these states as they are. That means you are not chasing any "happy" states or getting out of other states.

How do you link the illusion of self to intensified curiosity about the world? I've always had an intensified curiosity but I'm unable to link this to "self".

Thanks for this comment. I've added it to my list of 'things to process' :).

I'm inclined to agree with you, despite the fact that I often have immense trouble being mindful (which I think is basically what you're getting at), and will go for various kinds of 'junk food', whether television or food or gaming.

The times where I've managed to focus on 'sparser but deeper' endeavors, the result was always better in every way.