 One particularly interesting solution to the circularity problem is that provided by Peacocke 1984/1997. Peacocke defends what he calls an “experientialist’s version” of the theory, one which requires the introduction of a third property, besides those of being red, and looking red—a sensational property, that of being red*. According to this account, the property red is explained not in terms of looking red, but in terms of causing the perceiver to have presented to him, sensational properties in a visual field. (For discussion, see Boghossian and Velleman 1989/1997)