British novelist Samuel Butler wrote in Life and Habit (1878) that “[I]t has, I believe, been often remarked, that a hen is only an egg’s way of making another egg”.
When you eat an apple and leave behind, or eat, its core, from the perspective of the tree that brought into existence your apple you disperse its seeds. The tree is, in essence, using you as a vector for seed dispersal. There is a interrelated interest at play here. You eat the apple because you are hungry, or because you like to eat apples, or because you have otherwise a reason to do so. The tree brings its fruit to ripeness–an energy-demanding process largely consisting of sugar accumulation–to make it pleasurable to you. Unless you are very hungry, if the tree would not bring the apple to ripeness you would be less likely to eat it and, thus, to behave in the plant’s interest.
In my opinion, drawing boundaries between self and not-self is largely arbitrary, and to reduce the distance between self and not-self is a life-long exercise towards an awareness that connection, relatedness, can be shared with just about anything.
An idea that in my experience has been, time and again, one of the most powerful source of happiness.