By using animals in the austere and arbitrary style as they are used on the shields of heraldry or the hieroglyphics of the ancients, men have really succeeded in handing down those tremendous truths that are called truisms. If the chivalric lion be red and rampant, it is rigidly red and rampant; if the sacred ibis stands anywhere on one leg, it stands on one leg for ever. In this language, like a large animal alphabet, are written some of the first philosophic certainties of men. As the child learns A for Ass or B for Bull or C for Cow, so man has learnt here to connect the simpler and stronger creatures with the simpler and stronger truths. That a flowing stream cannot befoul its own fountain, and that any one who says it does is a tyrant and a liar; that a mouse is too weak to fight a lion, but too strong for the cords that can hold a lion; that a fox who gets most out of a flat dish may easily get least out of a deep dish; that the crow whom the gods forbid to sing, the gods nevertheless provide with cheese; that when the goat insults from a mountain-top it is not the goat that insults, but the mountain: all these are deep truths deeply graven on the rocks wherever men have passed.
It matters nothing how old they are, or how new; they are the alphabet of humanity, which like so many forms of primitive picture-writing employs any living symbol in preference to man. These ancient and universal tales are all of animals; as the latest discoveries in the oldest pre-historic caverns are all of animals. Man, in his simpler states, always felt that he himself was something too mysterious to be drawn. But the legend he carved under these cruder symbols was everywhere the same; and whether fables began with Aesop or began with Adam, whether they were German and mediaeval as Reynard the Fox, or as French and Renaissance as La Fontaine, the upshot is everywhere essentially the same: that superiority is always insolent, because it is always accidental; that pride goes before a fall; and that there is such a thing as being too clever by half. You will not find any other legend but this written upon the rocks by any hand of man. There is every type and time of fable: but there is only one moral to the fable; because there is only one moral to everything.
— Introduction to Aesop’s Fables (1912).