Let’s say you were to take a 6x6 sq foot area of empty space. This area could still have temperature, lightwaves, dark gravity (I think), and other elements that are too complicated for my brain.
The argument that Leslie is making is if you were subsequently subtract each of these things then you could arrive at nothing. And that makes sense to me.
It’s similar in my mind to the concept of null in computer science. Null is not zero. Null is void of value, which ironically means you can also pass null.
But then is an area containing light and gravitational waves something in the first place? Is it even possible to have an area with out gravitational waves? Even temperature is a relative construct, but we’d have to infer if the quest is to rid ourselves of all elements that absolute 0 must be the baseline.