As can be seen a crucial difference between SEE and many models of expertise is its indifference to scale and therefore ubiquity of expertise. In contrast to many philosophical and psychological models, SEE takes the ‘esotericity’ of an expertise to be a contingent matter rather than an essential property. Stage theories of expertise such as those of, Dreyfus and Dreyfus, or Chi, correctly describe some expertises but not others. This is because some expertises do not always pass through the standard stages (think of learning to balance on a bike or learning to articulate ‘tongue-twisters’) and because sometimes the stages are integral with growing out of infancy.Footnote 4 The 10,000 hours of self-conscious practice model does not always work for similar reasons. Most fatal of all for the idea that expertise is necessarily esoteric is that the same expertise can be esoteric at one time or place and ubiquitous at another. Thus, fluent English speaking is not-counted as an expertise in England but is a valuable skill in France while car-driving and word-processing were esoteric skills when cars and desk-top computers were first developed but are now widespread. The greatest damage caused by the ‘essentially esoteric’ view of expertise has arisen from mistaking ubiquitous expertises, such as native fluency in a language, as not really expertises at all because everyone possesses them. Thus did at least one set of ludicrous misunderstandings of the power of computers come into being, a misunderstanding that is still present in science fiction representations of robots where fluent speech is never a problem even though in the real world of computing fluent speech is a distant dream.
Understanding of expertise as essentially orthogonal to its ‘esotericity’ along with the SEE model of the acquisition of an expertise enables us to construct a three dimensional model of expertise—an ‘Expertise Space Diagram’—as shown in Fig. 4.
The front-to-back ‘Z-axis’ represents the usual philosophical or psychological ways of thinking about expertise—a matter of increasing individual accomplishment that may pass through certain definable stages. To this we can now add the, left-to-right, X-axis, which represents the extent to which an individual has access to the tacit knowledge of the domain in question such that he or she can gain fluency. Figure 1 shows one stick figure—the one toward the top left—who has no number indicating a practical specialism. We can think of this figure as a novice who is entering the field and has only started to acquire the language and the practical abilities and so has not yet developed into a specialist. If the novice is to succeed they must have good access to the tacit knowledge and will move to the right as they gain it. The, vertical, ‘Y-axis’ represents the esotericity of the domain, native English speaking being low down in English-speaking countries, GW physics being high in all known countries, though one can just about imagine a society where gravitational wave physics was taught from the cradle and in which it would be a ubiquitous expertise.
The expertise space diagram can be used in a number of ways. Figure 5 shows ‘surfaces’, in this case representing car driving. The top surface is represents racing-driving, an esoteric expertise. The back left hand void in these surfaces results from the impossibility of going far on the Z-axis without going far on the X-axis—i.e. acquiring tacit knowledge. There may be some skills where it is all, or nearly all, a matter of explication but they are hard to think of. The front right hand void is there because if a novice sticks around for a long time without starting to learn things—backward movement on the Z-axis—he or she is likely to be excluded from the company of experts. I guess the first of these voids is, roughly, philosophical and the second one is, roughly, sociological, but I must admit they both come from armchair consideration, though one based on lots of experience. The top surface could also represent car-driving when horseless carriages were first invented. The lowest surface represents ordinary driving in Western societies where the expertise is nearly ubiquitous. The middle surface can be an in-between position in time, in specialist driving skill (e.g. lorry-driving) or represent some location where there are few cars—some developing society.
Figure 6 shows educational trajectories. The left of these two is kindergarten where infants are being taught to acquire a range of skills—language, proper social interaction etc.—that are ubiquitous in the society in question. The rightmost of the two diagrams represents university education—distance learning, normal face-to-face degrees with more acquisition of tacit knowledge and Ph.D., which involves quite a bit more tacit knowledge.