Apollinaris "the Younger" (died 390) was a bishop of Laodicea in Syria. He collaborated with his father Apollinaris the Elder in reproducing the Old Testament in the form of Homeric and Pindaric poetry, and the New Testament after the fashion of Platonic dialogues, when the emperor Julian had forbidden Christians to teach the classics.
Best known, however, as a noted opponent of Arianism, Apollinaris' eagerness to emphasize the deity of Jesus and the unity of his person led him so far as to deny the existence of a rational human soul (νους, nous) in Christ's human nature, this being replaced in him by the logos, so that his body was a glorified and spiritualized form of humanity. Over against this the orthodox or Catholic position maintained that Christ assumed human nature in its entirety including the νους, for only so could He be example and redeemer. It was alleged that the system of Apollinaris was really Docetism, that if the Godhood without constraint swayed the manhood there was no possibility of real human probation or of real advance in Christ's manhood. The position was accordingly condemned by several synods and in particular by that of Constantinople (381).
This did not prevent its having a considerable following, which after Apollinaris's death divided into two sects, the more conservative taking its name (Vitalians) from Vitalis, the Apollinarist claimant to the see of Antioch, the other (Polemeans) adding the further assertion that the two natures were so blended that even the body of Christ was a fit object of adoration. The whole Apollinarian type of thought persisted in what was later the Monophysite school.
Apollinaris did make a lasting contribution to orthodox theology in declaring that Christ was consubstantial (of one substance) with the Father as regarding his divinity and consubstantial with us as regarding his humanity. This formula, which originated with Apollinaris, later became official orthodox doctrine. Apollinaris was also one of the first to claim that God suffered and died on the cross, a claim which received immediate condemnation but later became acceptable in orthodox theology .
Although Apollinaris was a prolific writer, scarcely anything has survived under his own name. But a number of his writings are concealed under the names of orthodox Fathers, e.g. ἡ κατα μερος πιστις, long ascribed to Gregory Thaumaturgus. These have been collected and edited by Hans Lietzmann.
Two letters of his correspondence with Basil of Caesarea are also extant, although there is scholarly debate regarding their authenticity because they record the orthodox theologian Basil asking Apollinaris for theological advice on the orthodox term 'homoousios'. However, these concerns are unfounded, as before Apollinarius began promulgating what were seen as heretical doctrines, he was a highly respected Bishop and friend of Athanasius and Basil.
He must be distinguished from the Apollinaris Claudius, bishop of Hierapolis, who bore the same name, and who wrote one of the early Christian "Apologies" (c. 170).