FIGURE 3.

Two options for how a set of domains on SC-space, representing the SCs that evoke specific qualia (the Qs), could derive by common descent from those evoking a single ur-quale (UQ). The intent is to show how the ur-quale is changed in character (horizontal axis) over evolutionary time (vertical axis). (A) The evaporating puddle scenario: this assumes an ur-quale whose SCs occupy a large domain, which is not then precisely defined at first with regard to the experiences those SCs evoke. A range of sensations would hence be evoked together from which the descendant qualia are progressively refined. Since the SCs remain within the parent domain, each newly evolved quale would incorporate elements present in the ur-quale. (B) The branched tree scenario: this assumes the SCs evoking the single ur-quale were distinct and well defined from the start, so the initial point cloud would have been restricted to a smaller domain compared with the puddle scenario. Since the branches of the tree diverge, all of the Qs in the tree scenario (in this example, all but Q3) will differ qualitatively from the ur-quale from which they all derive. See text for details.