Section — Wouters, Manual of Moral Theology
§ I. On Strict and Lax Conscience
I. He has a strict conscience who habitually, from a slighter reason, judges that something is a sin or a grave sin which involves no malice or only slight malice. One who labors under a strict conscience should strive to submit his mind to the judgment of wiser and more prudent persons, especially with regard to the direction of others.1 "It is indeed wrong to relax the observance of divine laws more than is permitted; but it is no less an evil to render the divine yoke harder for others than is fitting" (St. Alphonsus, I, 82).
1 Cf. Sweens, Theol. Mor. fund., n. 739.
II. He has a lax conscience who habitually, from a slighter reason, judges as licit what is illicit, or as venial sin what is mortal.
One who advertently acts according to the dictate of a lax conscience sins, because he rashly exposes himself to the danger of transgressing the law. Practically, however, not rarely it will be difficult to determine how far sufficient advertence, especially for sinning gravely, was present.
The principal causes of a lax conscience are: 1. bad education and association; 2. a soft and luxurious life; 3. the habit of sinning; 4. the reading of authors who are more benign than is just and easily depart from the stricter opinions of the masters of Moral Theology, especially St. Thomas and St. Alphonsus.
The principal remedies are: 1. removal of the causes set forth; 2. frequent confession made to a prudent confessor; 3. frequent and diligent examination of conscience; 4. assiduous prayer; 5. if there is question of clerics, reading of authors who press on in the footsteps of St. Thomas and St. Alphonsus. Concerning St. Alphonsus, the Decree by which the title of Doctor was granted testifies that "among the tangled opinions of theologians, whether laxer or stricter, he laid down a safe way" (n. 215).