Graves's emergent cyclical levels of existence (E-C theory or ECLET) is a theory of adult human development constructed from experimental data by Union College professor of psychology Clare W. Graves. It produces an open-ended series of levels, and has been used as a basis for Spiral Dynamics and other managerial and philosophical systems. Names Graves used a variety of names for his theory during his lifetime, ranging from the generic Levels of Human Existence in his earlier work to lengthy names such as Emergent Cyclical, Phenomenological, Existential Double-Helix Levels of Existence Conception of Adult Human Behavior (1978) and Emergent Cyclical Double-Helix Model of the Adult Bio-Pyscho-Social Behaviour (1981). In his posthumously published book, The Never Ending Quest, Graves titled the chapter introducing the theory "The Emergent Cyclical Model," and used the phrases "emergent cyclical conception" ("E-C conception") and "emergent cyclical theory" ("E-C theory") repeatedly as short names throughout the subsequent chapter on verifying his work. However, "levels of existence" is the more commonly known part of the phrase, and was used in the title of the peer-reviewed 1970 article in the Journal of Humanistic Psychology, the single such academic psychology publication Graves made during his lifetime (although he also presented at academic conferences). Graves himself considered the levels to be artifacts of the theory, therefore this article adopts the following conventions: emergent cyclical theory (E-C theory) is used for the theory itself levels of existence refers to the open-ended set of levels generated by the theory Gravesian theory, Gravesian thought, or ECLET is used when such precision is not needed, or when there is need to discuss the body of work as a whole Typographically, this article adopts the letter pair formatting chosen for The Never Ending Quest, which places the letters directly adjacent to each other (AN) rather than hyphenated (A-N). This is the form used in the manuscript abandoned in 1977. Graves used both hyphenated and unhyphenated forms, both before and after abandoning his manuscript. In contrast, in the same source "E-C" for "emergent cyclical" is always hyphenated. Motivation and experimental design Graves began his work in response to questions from his students regarding which of various conflicting psychological theories was correct. Rather than construct a hypothesis about how the conflicting systems could be resolved, Graves posed several open-ended questions and looked to see what patterns would emerge from his data. While not typical at the time, these