Pretty much the first time we meet the monster in Grendel, he's flipping the bird at whatever god might be watching him from the heavens. It's not too hard to figure out that Grendel has some major problems with the entire universe and his place in it.
Out of his suffering, baby Grendel constructs a theory of the world that stays with him until he runs up against Beowulf: that he alone exists, and that everything else is merely a product of his own perception. That's heavy stuff for a little critter, but it's not enough to answer the nagging questions he has about his identity and the relationship he has with mankind. Experience and the dragon have to flesh out these things for him.
Gardner uses Grendel and his role as evil outcast to make us think hard about all those things that we take for granted—like who we are, what our purpose in life is, and whether or not we're on the "right side." The big takeaway here? Everything seems to be relative and negotiable, depending on whose point of view you're seeing.
Questions About Life, Consciousness and Existence
What is Grendel's first encounter with humans? What are his first impressions of them?
Grendel is often irritated by creatures in the natural world. Why is this?
How does the visit to the dragon's lair change Grendel's ideas about his place in the universe?
What happens to Grendel's philosophy of the world around him when he meets Beowulf?
Chew on This
The Shaper's songs help Grendel to refute the philosophies of the dragon.
The dragon doesn't really tell Grendel anything that he doesn't already know.