 PLOT: Geordi LaForge and Ro Laren are accidentally cloaked and  phased, meaning that they become invisible and their molecules pass  through other matter (in other words, they are like ghosts).  However, they are still able to see normal matter, they are still  able to walk about the ship (they can pass through doors and walls,  but floors still work as usual?), they are still able to breathe  air, and they are still able to communicate with each other through  speaking (sound waves carried through the air)... none of which  should be possible if they are really cloaked and phased (they  shouldnt be able to interact with light or matter in any way).