α) The defenders of the _fides explicita_ theory are compelled to assume that God must somehow reveal to each individual heathen who lives according to the dictates of his conscience, the six truths necessary for salvation. “Faith cometh by hearing, and hearing by the word of Christ.”(563) But how can the gentiles believe in a revelation that has never been preached to them? Here is an undeniable difficulty. Some theologians say: God enlightens them interiorly about the truths necessary for salvation; or He miraculously sends them an apostle, as He sent St. Peter to Cornelius;(564) or He instructs them through the agency of an angel.(565) None of these hypotheses can be accepted as satisfactory. “Interior illumination” of the kind postulated would practically amount to private revelation. That God should grant a special private revelation to every conscientious pagan is highly improbable. Again, an angel can no more be the _ordinary_ means of conversion than the miraculous apparition of a missionary. Nevertheless, these three hypotheses admirably illustrate the firm belief of the Church in the universality of God’s saving will, inasmuch as they express the conviction of her theologians that He would work a miracle rather than deny His grace to the poor benighted heathen.(566) The difficulties to which we have adverted constitute a strong argument in favor of another theological theory which regards explicit belief in the Trinity and the Incarnation merely as a _necessitas praecepti_, from which one may be dispensed. β) The _fides implicita_ theory is far more plausible, for it postulates no miracles, implicit faith (or _fides in voto_) being independent of the external preaching of the Gospel, just as the baptism of desire (_baptismus in voto_) is independent of the use of water.