Yesterday's post on epistemology and geometry
suggests an Amazon customer review of Descartes's
Rules for the Direction of the Mind —
Quoted in that review —
"… we must make use of every assistance
of the intellect, the imagination, the senses,
and the memory" (Descartes, Rules, XII)
One such assistance is the calendar.
See the date of the Blasjo review, Dec. 20, 2009,
in this journal. See also Descartes.