Thus, the scission idea implies that the distal layer must have a lightness (or, to explain color scission, chromaticity) that is consistent with it being a continuation of the surround in which a target is embedded (Anderson, 1997; Ekroll and Faul, 2002). As Anderson (Anderson, 1997, p. 429) notes, without this ‘critical aspect of the present theory’ the predictions of scission would be ambiguous. Strict application of the scission concept implies that subjects should perceive a transparent green layer — a green filter — in front of a purplish plane in Fig. 1(c), due to phenomenal scission of the achromatic layer (the diamond) into complementary colors green and magenta. In informal observations using naive subjects, however, all of them report perceiving a black grid within the greenish diamond region of Fig. 1(c), not a continuation of the purple grid.