Negation of voidness

I recently came across the following statement in a book I'm reading: "If consciousness in a sentient being disappears, there is no cognizer; if there is no cognizing, there is no manifestation; indeed, there is nothing but voidness, and true apperception is the negation of this voidness." I have encountered this "negation of voidness" before but never really grasped it. I hope someone else can throw some light on it. Thank you.