The tertiary domain approximates to that of the propagation of pure evaluation, in the sense in which the secondary domain is that of the propagation of pure description. It is that of the imparities which become wishes when they are valued, liked, preferred or chosen by some observer. A tertiary machine would be one of which the chief capability is that of processing wishes or choices, but it does not matter how much information is lost in the process: it is open to information but closed to imparity...
...in the tertiary domain, a pure evaluation can be transmitted only if there is both a capability of liking one state of affairs or event more than another and also some transmissible feature of the event which can be differentially liked. This transmissible component we shall call 'imparity'.
Stewart, D J. A ternary domanial structure as a basis for cybernetics and its place in knowledge. Kybernetes 18, 4, 19-28, 1989.