IIT 3.x makes use of a distance function on a space probability distributions. The theory uses this space of probability distributions in order to construct a space which it claims is identical to conscious experiences. Both the individual spaces as well as the prodcts are instantiations of what is called an ''experience space'' in Kleiner & Tull, which includes the said distance function.
Whereas in IIT 3.x the distance function is an adaptation of the KL-divergence over probability distributiosn (cf. Kleiner & Tull for details), IIT introduces a new distance measure, called '''Intrinsic InformationDifference'''. ;Def.: Intrinsic Difference: TBA The justification for introducing this new distance