Persistence of Vision

In a “hermit crab essay,” one form of nonfiction is disguised inside another, its outer form at odds with creative prose: a shopping list, instruction manual, encyclopedia entry. The delicate flesh of the essay-crab is protected by a hard informational shell.¹ More often than not, the soft tissue of the hermit crab is made of memoir or personal essay, but there is no principled reason why it couldn’t go another way. Why not a shopping list disguised as a sermon, a side-effects label in the form of a concert review?

My favourite hermit crab—and perhaps my favourite book—is Peter Mark Roget’s Thesaurus, a treatise in foundational metaphysics disguised as a reverse dictionary.² Roget’s states his shell endeavour in the first edition of 1852:

The purpose of an ordinary dictionary is simply to explain the meaning of words; and the problem of which it professes to furnish the solution may be stated thus: — The word being given, to find its signification, or the idea it is intended to convey. Th…