Jon, when the Formula of Concord rejects a “carnal, Capernaitic” explanation of the Eucharist, it is not rejecting consubstantiation or any “philosophical” or “metaphysical” explanation of the Eucharist. It is merely speaking against the accusations of the “Sacramentarians” that a belief in the real presence of Christ in the sacrament implies cannibalism. Like St. Augustine says,
What is it, then, that He adds? “It is the Spirit that quickens; the flesh profits nothing.” Let us say to Him (for He permits us, not contradicting Him, but desiring to know), O Lord, good Master, in what way does the flesh profit nothing, while You have said, “Except a man eat my flesh, and drink my blood, he shall not have life in him?” Or does life profit nothing? And why are we what we are, but that we may have eternal life, which Thou dost promise by Your flesh? Then what means “the flesh profits nothing”? It profits nothing, but only in the manner in which they understood it. They indeed understood the flesh, just as when cut to pieces in a carcass, or sold in the shambles; not as when it is quickened by the Spirit. Wherefore it is said that “the flesh profits nothing,” in the same manner as it is said that “knowledge puffs up.” Then, ought we at once to hate knowledge? Far from it! And what means “Knowledge puffs up”? Knowledge alone, without charity. Therefore he added, “but charity edifies.” Therefore add to knowledge charity, and knowledge will be profitable, not by itself, but through charity. So also here, “the flesh profits nothing,” only when alone. Let the Spirit be added to the flesh, as charity is added to knowledge, and it profits very much. For if the flesh profited nothing, the Word would not be made flesh to dwell among us. If through the flesh Christ has greatly profited us, does the flesh profit nothing? But it is by the flesh that the Spirit has done somewhat for our salvation. Flesh was a vessel; consider what it held, not what it was. The apostles were sent forth; did their flesh profit us nothing? If the apostles’ flesh profited us, could it be that the Lord’s flesh should have profited us nothing? For how should the sound of the Word come to us except by the voice of the flesh? Whence should writing come to us? All these are operations of the flesh, but only when the spirit moves it, as if it were its organ. Therefore “it is the Spirit that quickens; the flesh profits nothing,” as they understood the flesh, but not so do I give my flesh to be eaten.
(Tractates on John XXII.5)
The passage from the Formula of Concord is teaching that Christ is present truly, but not in a carnal way that leads to cannibalism.
63] The other eating of the body of Christ is oral or sacramental, when the true, essential body and blood of Christ are also orally received and partaken of in the Holy Supper, by all who eat and drink the consecrated bread and wine in the Supper-by the believing as a certain pledge and assurance that their sins are surely forgiven them, and Christ dwells and is efficacious in them, but by the unbelieving for their judgment and condemnation, 64] as the words of the institution by Christ expressly declare, when at the table and during the Supper He offers His disciples natural bread and natural wine, which He calls His true body and true blood, at the same time saying: Eat and drink. For in view of the circumstances this command evidently cannot be understood otherwise than of oral eating and drinking, however, not in a gross, carnal, Capernaitic, but in a supernatural, incomprehensible way; 65] to which afterwards the other command adds still another and spiritual eating, when the Lord Christ says further: This do in remembrance of Me, where He requires faith [which is the spiritual partaking of Christ’s body).
Again, this is against the “Sacramentarians” who derided the Real Presence as blasphemy and cannibalism.
67] Hence it is manifest how unjustly and maliciously the Sacramentarian fanatics (Theodore Beza) deride the Lord Christ, St. Paul, and the entire Church in calling this oral partaking, and that of the unworthy, duos pilos caudae equinae et commentum, cuius vel ipsum Satanam pudeat, as also the doctrine concerning the majesty of Christ, excrementum Satanae, quo diabolus sibi ipsi et hominibus illudat, that is, they speak so horribly of it that a godly Christian man should be ashamed to translate it.
It is not rejecting “philosophical” or “metaphysical” explanations. Indeed, the authors of the Formula say that such explanations are necessary to define doctrine and, more to the point, that the distinction of substance and accident is an undeniable truth. I think it has been sufficiently demonstrated that the Formula’s teaching of “sacramental union” is a metaphysical explanation, making use of the metaphysical categories of substance, accident and so on.
