Complexity: Quantity or Quality

摘要

The term complexity is used informally both as a quality and as a quantity. As a quality, complexity has something to do with our ability to understand a system or object-people understand simple systems, but not complex ones. On another level, complexity is used as a quantity, when people talk about something being more complicated than another. In this article, the author explores the formalisation of both meanings of complexity, which happened during the latter half of the twentieth century.