Theory and practice of the confessional by Caspar Erich Schieler, Richard Frederick Clarke
III. A penitent who is guilty of gross neglect in the examination of conscience makes per se an invalid and sacrilegious confession; he must, of course, be sufficiently conscious of such neglect in order to incur this sin. The malice of the offence consists in the risk of omitting some mortal sin, and so, though none may have been actually left out, the penitent has sinned gravely by consciously exposing himself to the danger.IV. In order to make a good examination of conscience the penitent should adopt some system; the simplest and easiest method is to go through the commandments of God and of the Church, the various kinds of sins (especially the Seven Capital Sins), and the nine ways of participating in sin; it is also recommended to call to mind particular hours and days. Theologians give many other methods besides for this examination. Reuter recommends the penitent to recall where he was each day, what was done, and what sins were committed by thoughts, wishes, and desires, words, and works; how he has conducted himself at home, in church, with his neighbours; the author considers that by this means repetition will be avoided. To examine the conscience according to this method would be to exercise not only diligentia sufficiens but magna omnino diligentia. Sporer, approving the method recommended by Gobat, offers a compendious system for penitents who lead a fairly uniform existence and for whom the examination of conscience extends over a longer time, some months or half a year. The penitent should consider three periods: (1) an ordinary working-day; (2) a Sunday; (3) an exceptional day in which he has travelled, done some particular business, been present at a wedding or a dinner, etc. One who has only to examine a short interval may call to mind how he has sinned against God, his neighbour, and himself, by thoughts, words, and deeds.
