Employed skillfully, the metaphor is a powerful communication device. What better way to examine its effects than by visual metaphor? Suppose, modestly, that individual H is seeking to regale individual S with a captivatingly told account of an experience the former has had. Let the truth of the experience be a point centered within a sphere:

Understand that the ‘truth of the experience’ in no way refers to the notion of whether the experience occurred or not, but, rather, is intended to encompass how the experience registered perceptually in H. Notwithstanding that, for numerous reasons spanning the physical sciences as well as the arts, this truth is, at its most infinitesimally detailed level, unique to, and can only ever be known by, H, let the measure of correspondence between

1. The impression H’s narrative managed to render in S
2. The truth known only to H

be a combination of the alignment, with respect to the centered point, of an arrow whose length is the duration of the narrative, and the distance between the centered point and the arrowhead. For example, collapsing the sphere in two dimensions for the sake of clarity, compare the result when, on the left, H is a skilled raconteur, with when, on the right, H struggles socially:

The conspicuous absence of a definition for the spherical boundary, if not formerly a problem now certainly is, considering its implied significance as portrayed in the left sketch. Its meaning is readily discerned upon being informed that neither narrator is employing metaphor in their narration. The spherical boundary, then, simply represents the minimum distance achievable between the centered point of truth and a narration’s arrowhead when only literal language is used.

I contend that skillful use of metaphor is the means by which the boundary may be traversed. Describing something in terms of another frees elements of truth that otherwise remain inaccessible, as if locked and hidden in another dimension. The triumph of piercing the boundary comes at the cost of alignment, however, since a metaphor necessarily points to a truth different than that pointed to by literal language alone.

Having defined the correspondence between #’s 1 and 2, above, as being a function of two variables (alignment and distance), it’s clear that narrations absent of metaphor may be equivalent, with respect to correspondence, to narrations that employ the communication device. For example, all three narrations depicted below, one of which is exclusively literal, may be supposed to be equivalent in terms of their ability to render in S impressions corresponding equally closely to the truth known only to H.

At this point you may have guessed what is being suggested by the title of this post: if a single, well-conceived metaphor can breach the boundary, why shouldn’t a 2nd metaphor that builds on the 1st have the capacity to advance the arrowhead nearer the centered point? And who’s to say that stacked metaphors shouldn’t be graphically represented by vectors arranged head to tail? In the illustrations below, the dashed extension of the narrative is the Metaphor Vector vector-addition sum.

These may rightly be perceived as improvements over the prior examples of boundary-breaching narratives, as they yield arrowheads even nearer the centered point. Can they yet be bested? I believe they can. Witness the work of a metaphor master, whose vector-addition sum passes directly through the point of truth:

A natural outgrowth of this discussion is to wonder at how stacked metaphors might manifest. Here’s an initial attempt of mine, which, I’m afraid, is less stacked metaphor than single metaphor embellished with personification:

My wet leather boots had transformed overnight into sculpted, hollowed blocks of ice within which my feet, after emerging damp and cold from a poorly insulated sleeping bag, made contact with hostile and deceiving surfaces, surfaces whose nefarious reputation had been earned when their purported commitment to achieving the increase in local temperature that my feet so yearned for was recognized as insincere; this conclusion evident as soon as they reneged on promises to engage in the means that would precipitate such a desirable end, flatly refusing to accumulate and preserve the hopelessly faint emissions of warmth conveyed by my flesh and, worse, razing with abandon these most vulnerable emissions on receipt.