Extelligence
Extelligence is a term coined by Ian Stewart and Jack Cohen in their 1997 book Figments of Reality. They define it as all the cultural capital that is available to us in the form of tribal legends, folklore, nursery rhymes, books, videotapes, CD-ROMs, etc.
They contrast extelligence with intelligence (by which they mean the knowledge and cognitive processes within the brain). Further, they regard the ‘complicity’ of extelligence and intelligence as fundamental to the development of consciousness in both evolutionary terms for the species, and also for the individual. ‘Complicity’ is a composite of complexity and simplicity and Cohen and Stewart use it to express the close and interdependent relationship between knowledge-inside-ones-head and knowledge-outside-ones-head that one can readily access.
Although Cohen's and Stewart's individual disciplines are biology and mathematics, respectively, their description of the complicity of intelligence and extelligence is firmly in the tradition of Jean Piaget, Belinda Dewar and David A. Kolb. Philosophers, notably Popper, have also considered the relation between subjective knowledge (which he calls world 2), objective knowledge (world 1) and the knowledge represented by man-made artifacts (world 3).
One of the key contributions of Cohen and Stewart is the way they relate (through the idea of complicity) the individual to the pooled sum of human knowledge. From the mathematics of complexity and game theory they use the idea of phase space and talk about extelligence space. There is a total phase space (extelligence space) for the human race, which consists of everything that could be known and represented. Within this there is a smaller (but still enormous and rapidly expanding) set of what is actually known. What they propose is the idea that each individual can only access the parts of the total extelligence space with which their intelligence is complicit.
In other words, there has to be (at some level) an appreciation of what is out there and what it means. Much of this ‘appreciation’ falls into the category of tacit knowledge (Polanyi 1967) and social and cultural learning (Lave and Wenger 1991). As an example, a dictionary may contain definitions of many thousands of words. But only those definitions that can be understood by the reader, i.e. they can interpret the verbal symbols and relate them to concepts that her/his mind can work with, will be accessible.