Wuji wrote:This is quite the interesting question!
In old Viking legend, we hear about warriors that would enter a state (some of the time through trance, some of the time with mushrooms, or something else) that allowed them to fight in a way that was so natural and fluid, that it was as if they were in a state like this. There is a modern day recreation of this practice that still goes on today by some. George Xu spoke about different levels of advancement in practice, the highest being "energetic". This wasn't a point where you were throwing Qi around or anything. He talked about different mental states from doing the same things for so long. If you practice the same art for 30 years (less or more, each person is different), you get to a point to where you might enter into a state of mind like this. You might be more flowing, but I don't think that means you are any less lethal. I think it's more that you've trained the predator mind (reptilian brain) so much, that your conscious mind isn't what is in charge at this point, the animal inside is.
Native Americans would do Skin Dances around a fire to pull on the spirit of the Eagle or Bear, this is a good example. Over time, it wasn't them any longer, not there conscious mind. I'm prone to think it was being more connected to the reptilian brain. Not a fact or anything, just my own assumptions. I do think that starting out in martial arts with the idea of doing forms in a meditation like trance is the best way to go about it. I think this is very dance like. You have to progress through the movements, develop your Gong Fu. You have to lay the foundation and do the work way before this is should be done.
The Triune / Reptile Brain theory can be useful as a metaphor at a basic level, but has rather large holes in it from a scientific perspective.
Berserkers / mushrooms/trance states etc are all more to do with altering consciousness than flow states. Something of a flow state may be a side effect, but they are not quite the same thing. For me optimal flow state is being an optimum human being, not being "possessed" by the spirit of an animal or pretending to be something.
You can take any repetitive movement, chant or so on and use it to enter a trance state, but that won't necessarily put you in flow state, in some cases quite the opposite. Flow is about being alive and fully functional in the moment on all levels.