That's a concept

Tonight at dinner, we're discussing Wild Thing's efforts to grasp the concept of "nothing." Often he'll type some letters on the keyboard, then say: "What does that spell? It spells NOTHING!" Letters, of course, are also something he's been working on.

Tonight, looking out the window, he said, "I see NOTHING!"

Overworked Spouse: "I've noticed he's working on the concept of nothing."

WT: "Letters is a concept."

Indeed it is.