Given a very superficial understanding of Luhmann’s work, one might mistakenly associate it with the thought of Pierre Teilhard de Chardin (or other “vitalist” theories). The tenuous connection is that Teilhard’s theory deals with evolution and complexity.
Teilhard (1881-1955) was was a Jesuit priest and a paleontologist who was censored by the Catholic Church for his writings on evolution. He argued that evolution proceeds teleologically from inanimate matter (the geosphere) to living organisms (the biosphere) to the a level of human thought encompassing the planet, which he called the noosphere. The goal of evolution for Teilhard was called the Omega Point, which is identified with Christ or a universal Christ Consciousness. The idea is that evolution culminates in a singular point, where all separation is transcended.
The reason someone might confuse Teilhard’s theories with Luhmann, systems theory, or complexity theory is that Teilhard talked about increasing complexity and a sort of global system of thought, which might be called a system. You might even think of the noosphere as being autonomous and, like social systems, beyond the control of particular human beings. But for Luhmann, evolution is not teleological. Society, in Luhmannian theory, is a comprehensive social system; however, it does not consist of human thought but, rather, communication–and not just human communication. The reason human thought cannot evolve into some higher level beyond the biosphere is that thought cannot operate outside of psychic systems; thought must be transformed into meaningful communication in order to become social. There is also no sense in which social systems are “higher” than psychic or organic systems. Neither is any living organism higher in a ladder of evolution. Yes, evolution does produce more complexity, but this doesn’t imply a hierarchy or an Omega Point. The entire concept of hierarchy is associated with stratified society. But in a functionally differentiated society, there is no overall coordination among systems. There is no transcendent God that observes and organizes all of the systems.