It's literally the first sentence - the "part... in the machine". Also "reference point" (true aloneness would not offer such an insight), and "expectations from... others".
We all exist in nature, yet nurture plays such a heavy hand in us that we can barely separate out which is which or how much has derived from either. Unless we happen to have been part of twins separated at birth, then reunited, and studied - which many geneticists have made entire careers out of studying, like Francis Collins former Director of the National Institutes of Health until the pandemic. i.e., like the pandemic, whether we like it or not, we are affected by others who write so much of our stories that sometimes it's difficult to tell where "we" begin.
e.g. someone "daring to be different", just like everyone else, and people refusing vaccinations, bc someone told them to, etc. Our minds are a playground where others romp and play, and it's so EXTREMELY hard to even notice those effects, much less counteract them.
And should we even? Like I live in the USA, so I think "freedom" is nice, but someone living in e.g. China might enjoy more the feeling of existing in the constraints of a society that acts to take care of its citizens, e.g. with healthcare? Definitely the Nazis did not think much for personal freedoms, compared to the overall rights of the State. So how much of how "I" think was determined for me? Born into a country, a religion, a family, a culture, a people, am I even me?
Yes, but it has taken decades to arrive here, and most people refuse to follow, not my path I mean but their own. And how much of that is simply growing up, that everyone does, yet old people talk on Facebook and by sending chain emails, where us non-boomers don't like to follow? :-P I suspect it's rare, even if I have no proof, based on what I've seen so far.
So I am glad that you are exploring this dichotomy, between being "alone" vs. not, when the former is so extraordinarily difficult to truly arrive at that I suspect most people never get there in their entire lifetime. A truly remarkable achievement indeed, assuming it's even possible to ever actually get there - perhaps like walking to the moon on foot, it's merely a story that we tell ourselves to make us feel better?