In this paper, Manson (2001) presents a thorough review of complexity theory. I argue that Manson doesn’t make clear several concepts in his paper, such as the differences between chaos and complexity. Manson states that “there is no one identifiable complexity theory” and “any definition of complexity is beholden to the perspective brought to bear upon it”. He parses complexity into three streams of research: algorithmic complexity, deterministic complexity, and aggregate complexity. However, I don’t quite agree with this schema. Algorithmic complexity describes those systems that are so intricate that they are practically impossible to study. This problem cannot form part of the study of complex systems because it arises from an insufficient understanding of the system being studies or inadequate computational power to model and describe them. Therefore, algorithmic complexity may be a misleading movement away from complexity and its associated issues.
Even with many theoretical advancements and technical developments, complexity theory is still considered to be in its infancy, lacking a clear conceptual framework and unique techniques. Also, as Manson notes, it is important to explore “the ontological and epistemological corollaries of complexity”. Indeed, complexity has a relatively open ontology. It is necessary to consider the epistemology of complexity to understand the relationship between complexity ontology, emergence, and the balance between holism and reductionism.