chop your hand off. You will still remain. Remember your worst fever, you remained though your thoughts were muddled. Got separated from your partner? You still remained.

This is a form of self enquiry to separate yourself from what you are not, to break the spell of identification. Some people are identified with not only their bodies but with their children but to their car, house, job, even the products of their work. These are all not you.

After seeing what you are not, you start seeing what you really are. For that you will need this preparation work.

Yeah, I went through that process. I realized I am just the result of a biological process, in essence much like bacteria in a petri dish.

There is really no separation between the mind and the body.

We still don't fully understand consciousness, but we know most of our decision are taken unconsciously well before the conscious mind is aware of it. There are a myriad of books about this, but this wikipedia article is a good introduction:

https://en.wikipedia.org/wiki/Neuroscience_of_free_will

Come on, this meme thar is 'everything is cultural bias' is getting ridiculous.

It's not a meme, at least not in this case. If you can unlearn to identify with the monkey mind it probably means this is something you learned.