Canon 2200.1: "When an external violation of the law occurs,
in the external forum the existence of malice (dolus)
is presumed until the contrary is proved."
In the case of the crime of heresy: "The very commission
of any act which signifies heresy, e.g., the statement of
some doctrine contrary or contradictory to a revealed and defined
dogma, gives sufficient ground for juridical presumption
of heretical depravity… [E]xcusing circumstances have to
be proved in the external forum, and the burden of proof
is on the person whose action has given rise to the imputation
of heresy. In the absence of such proof, all such excuses
are presumed not to exist." (McKenzie, The Delict of
Heresy, CU Canon Law Studies 77, [Washington: 1932], 35.)
The reason such presumptions exist in the law, explain Abbo
and Hannon, is that "in the ordinary case man acts knowingly
and freely." (The Sacred Canons, [St. Louis: 1960], 2:788)
As regards the defense of ignorance, "If the delinquent
making this claim be a cleric, his plea for mitigation must
be dismissed, either as untrue, or else as indicating ignorance
which is affected, or at least crass and supine… His ecclesiastical
training in the seminary, with its moral and dogmatic theology,
its ecclesiastical history, not to mention its canon law, all
insure that the Church's attitude towards heresy was imparted
to him." (Ibid., 48)
McKenzie's teaching conforms to the general principle laid
down by the canonist Michels:
"'Given an external violation of the law, criminal intent
(dolus) is presumed in the external forum, until the
contrary is proven.' [canon 2200.2]
"This is obvious. For in the external forum one acts based
on the way things ordinarily happen and externally appear. And
indeed ordinarily, each person of sound mind customarily acts
reasonably and freely, fully knowing and deliberately willing
whatever he really does.
"Here the law rightly presumes that a violation of a law
takes place deliberately and freely, and thus with criminal
intent, until from concrete external circumstances the violation
of the law is proven to have been undertaken without any fault
(or at least grave moral fault) or out of juridical fault alone."
(De Delictis, 1:134)