Half a century ago, Stern discussed this attribute of an artistic object and called it apparency. While art is not limited to this single end, he felt that one of its two basic functions was "to create images which by clarity and harmony of form fulfill the need for vividly comprehensible appearance." In his mind, this was an essential first step toward the expression of inner meaning.
The personal experience of most of us will testify to this persistence of an illusory image long after its inadequacy is conceptually realized. We stare into the jungle and see only the sunlight on the green leaves, but a warning noise tells us that an animal is hidden there. The observer then learns to interpret the scene by singling out "give-away" clues and by reweighting previous signals. The camouflaged animal may now be picked up by the reflection of its eyes. Finally by repeated experience the entire pattern of perception is changed, and the observer need no longer consciously search for give-aways, or add new data to an old framework. They have achieved an image which will operate successfully in the new situation, seeming natural and right. Quite suddenly the hidden animal appears among the leaves, "as plain as day."
Everything points to the conclusion that the phrase 'the language of art' is more than a loose metaphor, that even to describe the visible world in images we need a developed system of schemata.
The far more pernicious issue with pangrams, as a means for evaluating typefaces, is how poorly they portray what text actually looks like. Every language has a natural distribution of letters, from most to least common, English famously beginning with the E that accounts for one eighth of what we read, and ending with the Z that appears just once every 1,111 letters. Letter frequencies differ by language and by era — the J is ten times more popular in Dutch than English; biblical English unduly favors the H thanks to archaisms like thou and sayeth — but no language behaves the way pangrams do, with their forced distribution of exotics. Seven of the most visually awkward letters, the W, Y, V, K, X, J, and Z, are among the nine rarest in English, but pangrams force them into every sentence, guaranteeing that every paragraph will be riddled with holes. A typeface designer certainly can’t avoid accounting for these unruly characters, but there’s no reason that they should be disproportionately represented when evaluating how a typeface will perform.