As so many who have explored Mahayana Buddhism before me, I’ve struggled with the notion of emptiness. I’ve tried to understand it through its analogues with space, but that can be a subtly dangerous metaphor. Emptiness is like space in many ways, but it’s not the same as space. Given the rough equivalence of emptiness and space, it’s very easy to slip from “emptiness is like space” to “emptiness is space.”
Six-hundred years ago in Tibet, Tsong Khapa explained it this way in his Ocean of Reasoning:
Just as space is not understood as anything but the mere absence of obstructions, such as mountains, reality should be understood as the mere absence of fabrications, such as mutability and instability.
I think that just about gets it all, the analogy and the distinction.