The things that can be known a priori can be named, but they can not be reduced. They are atomic concepts and the naming and defining of them are the same thing.
The room had the darkening light of dusk and incandescance mixed. The remaining conversations were relaxed and slow. It was a time for putting on of coats, and for feet on desks. The conversers had all had conciousness dawn on them gradually, and expected it to leave them gradually.
"It's happening", was the sudden exclamation of one of them, as he began swiftly removing the jacket he'd just buttoned up.