Laudator Temporis Acti

Augustine, Sermons 241.2 (Patrologia Latina, vol. 38, col. 1134; tr. Edmund Hill):

They could see their bodies, they couldn't see their souls. But they could only see the body from the soul. I mean, they saw with their eyes, but inside there was someone looking out through these windows. Finally, when the occupant departs, the house lies still; when the controller departs, what was being controlled falls down; and because it falls down, it's called a cadaver, a corpse. Aren't the eyes complete in it? Even if they're open, they see nothing. There are ears there, but the hearer has moved on; the instrument of the tongue remains, but the musician who used to play it has withdrawn.

Videbant corpus, animam non videbant. Sed corpus nisi de anima non videbant. Videbant enim per oculum, sed intus erat qui per fenestras aspiciebat. Denique discedente habitatore, iacet domus: discedente qui regebat, cadit quod regebatur: et quoniam cadit, cadaver vocatur. Nonne ibi oculi integri? Etsi pateant, nihil vident. Aures adsunt; sed migravit auditor: linguae organum manet; sed abscessit musicus qui movebat.

For the etymology of cadaver a cadendo see Robert Maltby, A Lexicon of Ancient Latin Etymologies (Leeds: Francis Cairns, 1991), p. 90:

TERT. resurr. 18,8 adeo cam est, quae morte subruitur, ut exinde a cadendo cadaver enuntietur (SERV. Aen. 6,481 caduci mortui, a cadendo: unde et cadavera dicta. SERV. auct. Aen. 11,143. HIER. in Matth. 24,28 I. 540. AUG. civ. 20,10 p. 432,29 D. 20,21 p. 461,24 D. AUG. serm. 241,2. AUG. quaest. hept. 3,20 p. 248,17. AUG. quaest. lev. 20,2. GREG. M. moral. 31,53. ISID. diff. 1,522. ISID. orig. 11,2,35).