Set-up #1: A person is enclosed in a container traveling with a constant velocity in the x direction. Wouldn't a laser inside the container attached to the floor and aimed perpendicular to the direction of travel (i.e., y direction) illuminate a spot on the ceiling of the container that is BEHIND a point marked on the ceiling directly above the laser, thus allowing the occupant to detect uniform motion in the x direction without external reference? As a laser photon traverses from floor to ceiling the container is moving and since light is not effected by the speed or direction of the source it will travel straight up. Set-up #2: A person is enclosed is in a container traveling with a constant velocity in the x direction. In the middle of the container is a lit light bulb. One spectrum analyzer is attached on the inside front wall and another analyzer attached on the inside back wall of the container. Wouldn't occupants be able to see different phasing due to the doppler shift and thereby detect their motion without external reference?