Perrennialism:

The dominant perspective in Transpersonal and Integral psychology has long been Perrennialism. It's vision of the unification of different traditions into a single universal ground or a single transcendent divine state It describes the evolution of consciousness, psychological development and human evolution as development toward a grand unification, eliminating differences. The bias is that all the different cultures and traditions of the world, all the different forms of consciousness are drawn from and find their ultimate expression in a singular unified consciousness, a singular state of being. This is a curious and particular bias that arguably emerges from the same instinct that gave rise to monotheism. Transhumanism also expresses this in its vision of an ultimate singular intelligence that is omniscient and all powerful that is attained when the technological singularity of neural complexity is achieved. In this perspective, a hierarchical model of consciousness and evolution predominate.

Pluralism:

Alternatively, a very different version of psychological, cultural technological and biological evolution can be described. Instead of a monism we can begin to envision a pluralism. From my view, each tradition and its forms of consciousness grow out of a different dynamic ground, emerging from its own native biome, culture, language, mythology, sacred plants and ritual practices.

To begin to see the differences, simply listen to the contemporary and traditional music of each culture, look at the art of each culture. What we find is variation and diversity, even when styles migrate from culture to culture. Different traditions have different grounds and practices, but also have different insights and experiences and can move toward different goals. As we have seen with Buddhism, Christianity and Islam, when people move a psycho-spiritual tradition to a different biome and culture, it changes and so the practices and experiences of people in those traditions change.

I would argue also that growth and development are not a simple linear hierarchical or holarchic process. We develop different capacities at different rates, rather than shifting wholly from one stage to the next. Where some people will develop spiritually, other might grow creatively, emotionally, intellectually, socially or in their relationship with the natural world. More complex video games provide a good analogy; where characters don't simply level up all their abilities at the same time but separately upgrade different capacities like constitution, strength, dexterity and intelligence.