The psychic paper is a blank, white card that, when shown to someone, allows the viewer to see whatever they wish to see or, in turn, allows the viewer to see whatever the holder of the card wants them to see. The Doctor often uses the psychic paper to facilitate his way into places, to gain people’s trust or to help him get out of difficult situations. The psychic paper can also be used to convey and receive messages, to open doors that required keycards, even functioning as a credit card. However, the paper doesn’t seem to work on everyone, notably failing to deceive people of genius or who lack imagination, showing itself as a simple blank card on those occasions.