Thus, protophenomenal properties have a kind of indirect definition, in terms of their propensity to ground consciousness. Different forms of panprotopsychism are distinguished by what if anything they have to say about the positive nature of protophenomenal properties. Many panprotopsychists think we currently have no positive conception of the nature of protophenomenal properties. Indeed, some have argued that we are constitutionally incapable of ever forming one. This view was dubbed “mysterianism” by Owen Flanagan, and is most associated with Colin McGinn (1989; McGinn does not use the label “panprotopsychism” to describe his view, but it fits the definition laid out in this section).