of spiral. For all such explanations and the like do not conflict with any clear evidence, if only in such details we hold fast to what is possible, and can bring each of these explanations into accord with the facts, unmoved by the servile artifices of the astronomers v. 'tThe waning of the moon and again her waxing a might be due to the rotation of the moon's body, and equally well to configurations which the air assumes ; further, it may be due to the interposition of certain bodies. In short, it may happen in any of the ways in which the facts within our experience suggest such an appearance to be explicable. But one must not be so much in love with the explanation by a single way as wrongly to reject all the others from ignorance of what can, and what cannot, be within human knowledge, and consequent longing to discover the indiscoverable. Further, the moon may possibly shine by her own light, just as possibly she may derive her light from the sun ; for in our own experience we see many things which shine by their own light and many also which shine by borrowed light. And none of the celestial phenomena stand in the way, if only we always keep in mind the method of plural explanation and the several consistent assumptions and causes, instead of dwelling on what is inconsistent and giving it a false importance so as always to fall back in one way or another upon the single explanation. The appearance of the face in the moon may equally well arise from interchange of parts, or from interposition of something, or in any other of the ways which might be seen to accord with the facts. For in all the celestial phenomena