Both types belong to the class of vocables that have been disarmed from its original context. The temporal context that gave rise to metaphors and functional vocabulary is increasingly absent in subsequent uses. Both are generalized to the point at which only a handful of features can apply to many contexts. Calvin suggests that the making of a metaphor involves loose-fitting structures activated from distributed attractors, layered from short-term memory to long-term memory, that can easily recall the underlying spatiotemporal foundation classes of more literal structures. This suggestion offers a convincing synaptic explanation that supports linguistic facts. Calvin also suggests the use of short cuts in times of quick responses, may contribute to the casual use of some vocables.
It may be that some of these short cuts are achieved through phase transition. These possibly give rise to structurally altered vocables, that play an essential functional role. The functional role played by vocables is different from metaphorical roles because it is structurally different. Metaphors result from competition in which schematic features try to match a spatio-temporal context. Functional vocabulary is probably not often involved in competition as its only connection to spatio-temporal structures are non-linguistic and prosody related (we will elaborate on that subject in the next chapter).
It is clear that a simple explanation cannot be given at this time for all the many ways we use vocables and how we come to have them. However a description of language that uses phase transition as part of its story has the additional advantage of offering a point of view that can explain the emergence of a variety of linguistic types and their role outside of the intervention of a psychological agent and in a completely predictable manner. Models that include attractors tend to be sensitive to initial conditions and have to be handled in a heuristic manner because the results they yield are not exactly predictable. Critical behavior, such as phase transition, is, on the other hand, formally well understood and predictable. The nature of a phase transition process is also such that it is universal because it is an observable feature of a number of natural phenomena, modeled in systems, such as in ferromagnetization behavior, and in macroscopic systems such as social percolation models.