Last night i was reading a chapter in Thich Nhat Hanh's The Sun My Heart in which he looked at the notion of interdependence and interpenetration. He used the analogy of organs in the body, where every organ depends on the blood to sustain it, which in turn depends on other organs like the heart to pump it, the lungs to oxygenate it, the digestive system to add nutrients, liver, kidneys etc to purify it and so on. Essentially, every organ depended on every other organ, and would not exist without the coordinated functioning of the whole. Indeed, every cell in the body depended on the whole body, which in turn is composed of all of those cells, so each cell is dependent on all the others. Each contains all the others, not in the sense of physically encompassing them (or even, as i thought of it, holding the DNA code) but in the sense that the existence of each cell implies the existence of the others. In a similar sense, though on a wider scale, the existence of anything implies the existence of everything else, one could not exist without the others existing, and thus even a speck of dust contains the entire universe.
Trying to get my head around the concept, i looked out the train window and thought about the things i could see. I looked at a street light above the Eastern Freeway and thought about how its existence depended on the conditions of our civilisation being as they are, in much the same way that my existence did. In fact, when i thought about all the history of civilisation, mankind, the world, the galaxy and the entire universe that went into making that street light possible, the vast chain of events, causes and conditions that led to that street light being there, without any of which it wouldn't be there, is overwhelmingly identical to the chain of events that led to me being there. Compared to that shared background, the bits of the universe's history which differ between my back story and the street light's are negligible, so it's reasonable to say that my existence and the street light's existence are fundamentally connected. My existence implies the street light's existence, the street light's existence implies my existence. The street light and i contain each other. We are connected, just as everything is connected.
But, you say, that's all well and good for the links between myself and a street light a few dozen meters away, products of the same civilisation on the same planet, but what about this cup on my desk and an atom radioactively decaying in some distant galaxy? How are they linked? Well, i can only guess that if you go back far enough, at some time and place (or maybe various times and places) the conditions that would eventually lead to that atom decaying in that corner of that galaxy would have coincided here and there with those that would lead to that cup sitting there, and if any were changed, neither the cup nor the atom would be as they are. Therefore the cup is dependent on the decaying atom, and the decaying atom on the cup.
(The next step in this line of reasoning would appear to be the sticky question of predestination and the awkward issues of free will that come with it, but that can wait for another time).