on to mental reservations. If they are
contained within the bounds of piety and sincerity, then they are not
necessary; ... but if [otherwise] they are the destruction of human
society and sincerity, and are to be condemned as pestilent. Once
admitted, they open the way to all lying, all perjury. And the whole
difference in the matter is, that what yesterday was called a lie,
changing, not its nature and malice, but its name, is today entitled
'mental reservation;' and this is to sweeten poison with sugar, and
to colour guilt with the appearance of virtue."

St. Thomas

"When the sense of the party swearing, and of the party to whom he
swears, is not the same, if this proceeds from the deceit of the
former, the oath ought to be kept according to the right sense of the
party to whom it is made. But if the party swearing does not make use
of deceit, then he is bound according to his own sense."

St. Isidore

"With whatever artifice of words a man swears, nevertheless God who
is the witness of his conscience, so takes the oath as he understands
it, to whom it is sworn. And he becomes twice guilty, who both takes
the name of God in vain, and deceives his neighbour."

St. Augustine

"I do not question that this is most justly laid down, that the
promise of an oath must be fulfilled, not according to the words of
the party taking it, but according to the expectation of the party to
whom it is taken, of which he who takes it is aware."

And now, under the protection of these authorities, I say as
follows:--

Casuistry is a noble science, but it is one to which I am led,
neither by my abilities nor my turn of mind. Independently, then, of
the difficulties of the subject, and the necessity, before forming
an opinion, of knowing more of the arguments of theologians upon it
than I do, I am very unwilling to say a word here on the subject of
lying and equivocation. But I consider myself bound to speak; and
therefore, in this strait, I can do nothing better, even for my own
relief, than submit myself and what I shall say to the judgment of
the Church, and to the consent, so far as in this matter there be a
consent, of the Schola Theologorum.

Now, in the case of one of those special and rare exigencies or
emergencies, which constitute the _justa causa_ of dissembling or
misleading, whether it be extreme as the defence of life, or a duty
as the custody of a secret, or of a personal nature as to repel an
impertinent inqui