From the Phenomenology to the Mechanisms of Consciousness: Integrated Information Theory 3.0
(A) An unconscious photodiode DO without recurrent connections. The detector element D affects output element O, but has no cause within the system DO. O is caused by D, but has no effect on the photodiode DO. Therefore, the elements do not form a complex and generate no quale. (B) Even complicated systems cannot form a complex if they have a strictly feed-forward architecture. This can be understood in the following way: for any system background imposed by an observer, the system's input layer has no causes within the system and the output layer has no effects on it, regardless of the elements' (logic) functions. Consequently, the system cannot form a complex and it remains unconscious, just like the unconscious photodiode DO.