According to the
Oxford Concise Dictionary of the Christian Church "by the early 5th cent., the word had become a technical term in Christian asceticism, signifying a state of restlessness and inability either to work or to pray." Not only monks and theologians spoke of the vice, but it appears in the writings of laymen, as well. It appears in Dante's
Divine Comedy not only as a sin to be punished in the damned, but also as the sin that leads Dante to the edge of Hell to begin with.
Chaucer's parson includes acedia in his list of vices. It follows
anger and
envy in the list and the parson connects the three vices together: For Envye blindeth the herte of a man, and Ire troubleth a man; and Accidie maketh him hevy, thoghtful, and wrawe. / Envye and Ire maken bitternesse in herte; which bitternesse is moder of Accidie, and binimeth him the love of alle goodnesse. In his sustained analysis of the vice in Q. 35 of the
Second Part (Secunda Secundae) of his
Summa Theologica, 13th-century theologian
Thomas Aquinas identifies acedia with "the sorrow of the world" (compare
Weltschmerz) that "worketh death" and contrasts it with that sorrow "according to God" described by
St. Paul in 2 Cor. 7:10. For Aquinas, acedia is "sorrow about spiritual good in as much as it is a Divine good." It becomes a
mortal sin when reason consents to man's "flight" (
fuga) from the Divine good, "on account of the flesh utterly prevailing over the spirit." Acedia is essentially a flight from the divine that leads to not even caring that one does not care. The ultimate expression of this is a despair that ends in
suicide. Aquinas's teaching on acedia in Q. 35 contrasts with his prior teaching on charity's gifted "spiritual joy", to which acedia is directly opposed, and which he explores in Q. 28 of the
Secunda Secundae. As Aquinas says, "One opposite is known through the other, as darkness through light. Hence also what evil is must be known from the nature of good." ==Modern revival==