Rejecting accepted definitions is fine if you have a purpose for doing it. The problem with Chapman is more that he's very sloppy with his langauge. If you read his blog, you might be left with the impression that Nietzsche is just some simple pseudo-mystical bullshitter, because Chapman doesn't explain Nietzsche's double movement from knowing to unknowing and vice versa. To use Chapman's own taxonomy, what Chapman thinks he's doing is dwelling in the space between meaningfulness and meaninglessness, but he's just being meaningless while expecting Nietzsche to somehow do the heavy lifting. Nietzsche probably would've hated this guy.