We argue that people’s finite conceptual horizons are a pervasive
and powerful constraint on how they make sense of the world.
These horizons represent the hard boundaries of where people’s
possible interpretation of their circumstances can go, and define the
finite channels into which their understanding is funneled.
To be sure, what each individual person knows is considerable, but it
pales against the entire landscape of concepts that are possible to know.
The typical 20-year-old English speaker knows the equivalent
of 42,000 dictionary entries, with the number rising to 48,000
by age 60 (Brysbaert, Stevens, Mandera, & Keuleers, 2016).
Webster’s Third New International Dictionary, however, contains
roughly 470,000 entries; the second edition of the Oxford English
Dictionary contains over 600,000.