It is sometimes erroneously supposed that such illustrations as this are intended to explain how the Sacred Mystery in question is possible, whereas they are merely intended to shew that the words we use concerning it are not self-contradictory, which is the objection most commonly brought against them. To say that the doctrine of the Son’s generation does not intrench upon the Father’s perfection and immutability, or negative the Son’s eternity, seems at first sight inconsistent with what the words Father and Son mean, till another image is adduced, such as the sun and radiance, in which that alleged inconsistency is seen to exist in fact. Here one image corrects another; and the accumulation of images is not, as is often thought, the restless and fruitless effort of the mind to enter into the Mystery, but is a safeguard against any one image, nay, any collection of images being supposed sufficient. If it be said that the language used concerning the sun and its radiance is but popular not philosophical, so again the Catholic language concerning the Holy Trinity may, nay must be, economical, not adequate, conveying the truth, not in the tongues of angels, but under human modes of thought and speech.