Chapter — Merkelbach, Summa Theologiae Moralis
Chapter III: On the Formation of a Right and Certain Conscience
¶1.
In the Case of Uncertainty and Error Together.
It can happen that conscience labors under a double defect and, on the part both of object and of subject, lacks the required qualities, namely, if it is erroneous and at the same time uncertain. And therefore it must especially be seen how in this case the principles already explained are to be applied, so that in practice a conscience at once right and certain can be formed. Here there occurs to be treated: