XLII. For it follows of necessity, since the imagination is unstable, that the judgment formed by it must be unstable likewise; (171) and there are many reasons for this. In the first place, the differences which exist in animals are not in one particular only, but are unspeakable in point of number, extending through every part, having reference both to their creation and to the way in which they are furnished with their different faculties, and to their way of being supported and their habits, and to the manner in which they choose and avoid different things, and to the energies and motions of the outward senses, and to the peculiar properties of the endless passions affecting both the soul and body. (172) For without mentioning those animals which have the faculty of judgment, consider also some of those which are the objects of judgment, such as the chameleon and the polypus; for they say that the former of these animals changes his complexion so as to resemble the soils over which he is accustomed to creep, and that the other is like the rocks of the sea-shore to which it clings, nature herself, perhaps, being their saviour, and endowing them with a quality to protect them from being caught, namely, with that of changing to all kinds of complexions, as a defence against evil. (173) Again, have you never perceived the neck of the dove changing colour so as to assume a countless variety of hues in the rays of the sun? is it not by turns red, and purple and fiery coloured, and cinereous, and again pale, and ruddy, and every other variety of colour, the very names of which it is not easy to enumerate? (174) They say indeed that among the Scythians, among that tribe which is called the Geloni, most marvellous things happen, rarely indeed, but nevertheless it does happen; namely that there is a beast seen which is called the tarandus, not much less than an ox in size, and exceedingly like a stag in the character of his face. The story goes that this animal continually changes his coat according to the place in which he is, or the trees which he is near, and that in short he always resembles whatever he is near, so that through the similarity of his colour he escapes the notice of those who fall in with him, and that it is owing to this, rather than to any vigour of body, that he is hard to catch. (175) Now these facts and others which resemble them are visible proofs of our inability to comprehend everything.