““If there is seeing without perceiving, there is also perceiving without seeing. If Ruby B were invisible we could infer her presence from your anomalous wobbling. Brown dwarfs and super-Jupiters and black holes, though hidden from sight, can be inferred from the anomalies they cause in their seeable neighbors. Much divergent behavior, in fact, is caused by invisible companions, although implied existence is not certain existence. Not everyone who stumbles stumbles on an invisible bandicoot.””
