Wilber's model of consciousness consists of three broad developmental categories: the prepersonal or pre-egoic, the personal or egoic, and the transpersonal or trans-egoic. A more detailed version of this model includes nine different levels of human development, in which levels 1-3 are pre-personal levels, levels 4-6 are personal levels and levels 7-9 are transpersonal levels. Later versions also include a tenth level. The transpersonal stages, or the upper levels of the model, are the home of spiritual events and developments. The framework proposed by Wilber suggests that human development is a progressive movement through these stages of consciousness. The theory implies that different schools of psychology are associated with different levels of the model, and that each level of organization, or self-development, includes a vulnerability to certain pathologies associated with that particular level. Each level also represents developmental tasks that must be properly met, or they might lead to developmental arrest. A basic tenet of Wilber's transpersonal psychology is a concept called the "pre/trans fallacy". That is, a confusion of transpersonal progression with prepersonal regression. According to writers in the field western schools of psychology have had a tendency to regard transpersonal levels as pathological, equating them with regressive pathological conditions belonging to a lower level on the model. The pre/trans fallacy describes a lack of differentiation between these two categories.