Artificial Intelligence (AI) is an absolute key term in contemporary digital reality; it has become an umbrella term for a wide range of technologies developing rapidly, spanning and influencing diverse sectors and domains and, thereby, also, having a greater and greater impact on how more and more people live their daily lives and/or do their work. Public discourse on AI often involves metaphor or other imagery and a common way to represent AI is by what we call the visual “blue brain metaphor”. This visual metaphor is frequently used by a number of rather diverse addressers (stakeholders) to capture essential elements of AI by conferring to it human-like characteristics.
In the following we describe the semiosic background of the “blue brain metaphor” for AI; that is, inspired by the terminology of Umberto Eco, we understand the metaphor as a function of the socio-cultural format of the encyclopedia which decides the relevant relations of similarity between AI and the human brain underlying the metaphorical production and interpretation. We address what characterizes the “blue brain metaphor” visually and try to interpret (some of) its meanings, also accentuating how it builds on to the (old) metaphor the ”computer is a brain”. And, finally, we briefly describe how the “blue brain metaphor” is related to diverse normative discourse concerning AI.