i totally agree with the "all the people living in this world are interrelated and the future wellbeing of one individual is linked with that of the world's entire x billion people" statement and extends it to any other thing in the whole universe.
i acknowledge the concept of "without you, without me", which is very real.
on one level, i know there is "me" because there is "you" - the external world, anything that is outside of the perceived "me". without an opposing "you", how can i define and draw a boundary of what is "me" and "my" things?
on another level, i know there is "me" right here right now because "you" - may it be any human, insects, animals or any supernatural beings or any phenomena, have not disallowed me to exist (eg. harmed me) thus my dependence on "you" for "me" to exist.