Imperceptible

"These examples and many others demonstrate an alarming trend whereby the privacy and dignity of our citizens is being whittled away by sometimes imperceptible steps. Taken individually, each step may be of little consequence. But when viewed as a whole, there begins to emerge a society quite unlike any we have seen -- a society in which government may intrude into the secret regions of man's life at will."
--William O. Douglas,
Dissenting, Osborn v. United States, 385 U.S. 323, 343 (1966).