AGNOSIANS. - A sect connected to Severian Monophysitism, so named because it attributes to the human soul of the incarnate Word ignorance (ἄγνοια in Greek) of certain things, and in particular of the day of the last judgment. The head of the A. was the Alexandrian deacon Themistius (v.), a disciple of Severus of Antioch. Shortly after the latter's death (538), around 540, under Theodore (535-67), Monophysite patriarch of Alexandria, Themistius began to spread his doctrine. When Theodore rejected him as a heretic, Themistius separated from him and became the master of a separate sect that called itself that of the Agnoetae or Themistians, in opposition to that of the Theodosians, which gathered the majority of the Severian Monophysites.
Long before Themistius, various orthodox Fathers who fought Arianism had positively taught, or seemed to have taught, that Jesus Christ, as man, had been ignorant of various things, and particularly of the day of Judgment. Concerned with defending the divinity of the Word against the Arians, and not having sufficiently deepened their understanding of the nature of the hypostatic union so as to know all its consequences, they had attributed to the humanity of the Savior the ignorance of the day of Judgment that the Arians wanted to attribute to the Word. Such an opinion could no longer be accepted after a century of discussions and speculations on the hypostatic union and, at most, could only appeal to the Nestorians; and it was in this category that Catholic and Monophysite polemicists classified the Themistians. Theodore of Mopsuestia and Nestorius had been Agnoetae even before Themistius; and so too had the Gallic monk Leporius (v.), who had taken refuge at Hippo in the time of St. Augustine, and had later disavowed his own error (PL 31, 1229).
There were always some Agnoetae over the course of the centuries, and there are even some in our own era. Although certain Fathers, such as St. Sophronius of Jerusalem and St. John Damascene, branded agnoetism as heresy, it must be considered rather an error, given the strict sense in which the name heresy is taken today. This is deduced from a decree of the Holy Office of June 7, 1918, prompted by the agnoetist tendencies of certain contemporary theologians. This decree states that the following two propositions cannot be taught with certainty: 1) The doctrine that declares that the soul of Jesus Christ was ignorant of nothing, but knew in the Word, from the beginning, the past, the present and the future, that is to say all that God knows with the knowledge of vision, cannot be held as certain; 2) The opinion of certain recent authors on the limited knowledge of Jesus Christ has as much right to be accepted in Catholic schools as the doctrine of the ancients on his universal knowledge.