One of the big questions of Beresheet is this: what is in and what is out? Or, put differently: who is us, and who is we?

The first chapter of Beresheet tells the story of God’s creation of Heaven and Earth in six days. One of the keywords of this chapter is “l’havdil,” to separate–from which we get the word Havdallah, the separation ceremony by which we mark the end of Shabbat. God divides constantly during the story of chapter 1, separating light from dark, waters above from waters below, and land from water. Another keyword of the chapter is “min,” or species. Grasses and trees are created according to individual species, as are animals.

All of this creates an atmosphere of order out of tohu va’vohu, the primordial chaos the Torah says existed before Creation. In order to create that order, separation is essential–one has to separate what from what, creating unique kinds and species. And in doing so, one has to decide what is in and what is out, what is part of one category and what is part of another.

This is the basic work of human beings, the foundation of language itself. We order, we categorize, we separate. If we didn’t do this, we could not have a world.

This theme of separation, of in and out, is also found in the second chapter, when Adam and Eve ultimately eat of the fruit of the tree of knowledge of good and evil, and are cast out of Eden. The serpent tells Eve that, if she eats of the fruit, she will become “like God.” The great medieval interpreter Rashi comments on this phrase that, to be like God is to be “a creator of worlds.”

Up until this point, Adam and Eve have simply lived in the world–naked and unembarrassed as the Torah tells us. (Naked–with no separation from the world around them through clothing.) Without this separation, they cannot be creators, they cannot imagine the world as it might be–they can only accept it as it is. They have no imagination, no moral consciousness. When they eat from the fruit, their world is changed. They become separated from it–still in it, but out of it too: different, with a vision of what it might be. That is, they become human.

A third and final manifestation of the question of separation, of in and out, is in the Cain and Abel story. The line that stays with us from this story is after Cain kills Abel and God asks him, Where is Abel your brother? Cain responds, “Am I my brother’s keeper?” The French philsopher Vladimir Jankelevitch described the hatred of brothers as the “hatred of the almost-same.” That is, brothers–who share parents, who share chromosomes–are so alike that they sometimes feel the need to forcefully differentiate themselves, to say, “I am not you.” This is one way to read the Cain and Abel story, as the ultimate separation of otherness in the face of near-sameness. Cain wants Abel out–out of his world, and out of the world entirely.

Ultimately it is this theme that will play out over and over again throughout the book of Genesis, as the Torah asks us repeatedly, How can brothers learn to live togehter? How can we learn to separate in and out in a way that honors our differences, rather than eliminating them; that revels in diversity, instead of smothering it? How can we be in and out at the same time?