Individuation

The principle of individuation, or , describes the manner in which a thing is identified as distinguished from other things.
The concept appears in numerous fields and is encountered in works of Leibniz, Carl Gustav Jung, Gunther Anders, Gilbert Simondon, Bernard Stiegler, Friedrich Nietzsche, Arthur Schopenhauer, David Bohm, Henri Bergson, Gilles Deleuze, and Manuel De Landa.
Usage.
The word "individuation" occurs with different meanings and connotations in different fields.
In philosophy.
Philosophically, "individuation" expresses the general idea of how a thing is identified as an individual thing that "is not something else". This includes how an individual person is held to be different from other elements in the world and how a person is distinct from other persons. By the seventeenth century, philosophers began to associate the question of individuation or what brings about individuality at any one time with the question of identity or what constitutes sameness at different points in time.
In Jungian psychology.
In Jungian or analytical psychology, individuation is the process where the individual self develops out of an undifferentiated unconscious – seen as a developmental psychic process during which innate elements of personality, the components of the immature psyche, and the experiences of the person's life become, if the process is more or less successful, integrated over time into a well-functioning whole. Other psychoanalytic theorists describe it as the stage where an individual transcends group attachment and narcissistic self-absorption.
In the media industry.
The media industry has begun using the term "individuation" to denote new printing and online technologies that permit mass customization of the contents of a newspaper, a magazine, a broadcast program, or a website so that its contents match each individual user's unique interests. This differs from the traditional mass-media practice of producing the same contents for all readers, viewers, listeners, or online users.
Communications theorist Marshall McLuhan alluded to this trend when discussing the future of printed books in an electronically interconnected world.
In privacy and data protection law.
From around 2016, coinciding with increased government regulation of the collection and handling of personal data, most notably the GDPR in EU Law, individuation has been used to describe the ‘singling out’ of a person from a crowd – a threat to privacy, autonomy and dignity. 
Most data protection and privacy laws turn on the identifiability of an individual as the threshold criterion for when data subjects will need legal protection. However privacy advocates argue privacy harms can also arise from the ability to disambiguate or ‘single out’ a person. Doing so enables the person, at an individual level, to be tracked, profiled, targeted, contacted, or subject to a decision or action which impacts them - even if their ‘identity’ is not known (or knowable). 
Rapid advances in technologies including Artificial Intelligence, and optical surveillance coupled with facial recognition systems have now altered the digital environment to such an extent that ‘not identifiable’ is no longer an effective proxy for ‘will suffer no privacy harm’, and many data protection laws may require re-drafting to give adequate protection to privacy interests, by explicitly regulating individuation as well as identification of individuals.
In physics.
Two quantum entangled particles cannot be understood independently. Two or more states in quantum superposition, e.g., as in Schrödinger's cat being simultaneously dead and alive, is mathematically not the same as assuming the cat is in an individual alive state with 50% probability. The Heisenberg's uncertainty principle says that complementary variables, such as position and momentum, cannot both be precisely known – in some sense, they are not individual variables. A "natural criterion of individuality" has been suggested.
Arthur Schopenhauer.
For Schopenhauer the "principium individuationis" is constituted of time and space, being the ground of multiplicity. In his view, the mere difference in location suffices to make two systems different, with each of the two states having its own real physical state, independent of the state of the other.
This view influenced Albert Einstein. Schrödinger put the Schopenhaurian label on a folder of papers in his files “Collection of Thoughts on the physical Principium individuationis.”
Carl Jung.
According to Jungian psychology, individuation () is a process of psychological integration. "In general, it is the process by which individual beings are formed and differentiated [from other human beings]; in particular, it is the development of the psychological individual as a being distinct from the general, collective psychology."
Individuation is a process of transformation whereby the personal and collective unconscious are brought into consciousness (e.g., by means of dreams, active imagination, or free association) to be assimilated into the whole personality. It is a completely natural process necessary for the integration of the psyche. Individuation has a holistic healing effect on the person, both mentally and physically.
In addition to Jung's theory of complexes, his theory of the individuation process forms conceptions of an unconscious filled with mythic images, a non-sexual libido, the general types of extraversion and introversion, the compensatory and prospective functions of dreams, and the synthetic and constructive approaches to fantasy formation and utilization.
"The symbols of the individuation process . . . mark its stages like milestones, prominent among them for Jungians being the shadow, the wise old man . . . and lastly the anima in man and the animus in woman." Thus, "There is often a movement from dealing with the persona at the start . . . to the ego at the second stage, to the shadow as the third stage, to the anima or animus, to the Self as the final stage. Some would interpose the Wise Old Man and the Wise Old Woman as spiritual archetypes coming before the final step of the Self."
Gilbert Simondon.
In "L'individuation psychique et collective", Gilbert Simondon developed a theory of individual and collective individuation in which the individual subject is considered as an effect of individuation rather than a cause. Thus, the individual atom is replaced by a never-ending ontological process of individuation.
Simondon also conceived of "pre-individual fields" which make individuation possible. Individuation is an ever-incomplete process, always leaving a "pre-individual" left over, which makes possible future individuations. Furthermore, individuation always creates both an individual subject and a collective subject, which individuate themselves concurrently. Like Maurice Merleau-Ponty, Simondon believed that the individuation of being cannot be grasped except by a correlated parallel and reciprocal individuation of knowledge.
Bernard Stiegler.
The philosophy of Bernard Stiegler draws upon and modifies the work of Gilbert Simondon on individuation and also upon similar ideas in Friedrich Nietzsche and Sigmund Freud. During a talk given at the Tate Modern art gallery in 2004, Stiegler summarized his understanding of individuation. The essential points are the following: