Any system is, for itself, somehow “individual”. A mind is always individual, it is a unique and singular psychic system. Similarly, human bodies are unique and, to a certain extent, singular systems. Even communication systems may be called “individual”…
Thus individuality still exists in system theory, but as systemic individuality. The traditional “human being” is not such an individual, it is rather divided into at least three segments that each form individualities. A human being is born with an individual body, it builds up an individual mind, and will partake in many individual communication systems.
Social systems theory does not deny that there is a kind of individuality to the mind or the psyche (the “soul” in Old European philosophies). But, unlike in Old European philosophies (most notably the Cartesian tradition, this individuality can neither claim to be the “essential” nor the only true “individual” aspect of a human being.
From a systemic point of view, the bodily and the communication systems have the same degree of “individuality” as the psychic system and these individualities do not converge or exist in a hierarchical relation. Unlike Old European philosophies, there is no mind-body dualism. There is rather a mind-body-communication trinity, and within this trinity no system can “take control”. It was common in Old European philosophy to claim that the “intellect” should somehow rule over the body. Given the systemic “individuality” of systems, they are unable to exert controll over each other.
Traditional humanist notions are too simple to explain the complexity of reality - this is why there needs to be a new theory.... Luhmann replaces the notion of a singularly integrated human being with the assumption of a least three autopoetic systemic realms: body, consciousness, and communication.
"We" are a complex assembly of bodily functions, psychic operations, and social performances. Human beings are not "one-dimensional", but that least three-dimensional - and the three-dimensions are by no means in perfect harmony. We cannot exactly translate our mental contents into communication, and neither can the thoughts of our mind translate the exact physical processes of the brain. The Aristotelian concept that mental contents are the same for all human beings has become obsolete. And it is not only the belief in a common human "mindset" that has waned - the corresponding conception of the human being as a singular entity is also beginning to fade.
Traditional Old European philosophies... were often ready to concede that human beings are not simply made to of a "soul", but also of a body. However, these traditional views... tended to look at the soul as the seat of human "individuality" and thus as the essential element that defined the human being.
The soul was the essential element within the human body, and the body was acknowledged to be a more or less integral part of actual human existence. On the basis of this idea, the human being was conceived of as a singular compound of mind and body. Various traditional philosophies then discussed the so-called mind-body problem - how a singular entity could consist of two parts. Social systems theory does not offer a new and easy solution to this old problem, it rather suggests that "human reality" is even more complex: we do not only have to deal with the mind and the body - we also have to take into account communication. And in the face of such multiplicity it might be wise to give up the attempt still to "singularize" the human being.
Note: one may detect here the faint resemblance to Freud's famous dissection of the human psychic identity into three non-congruent and rather contradictory forces: the id, the ego, and the super-ego.