To all appearance, the thing would be as unthinkable in all those countless cosmic variations of forgotten eons as it would be in the beasts and birds before our eyes. The child would no more expect to see it than to see the cat scratch on the wall a vindictive caricature of the dog. The childish common sense would keep the most evolutionary child from expecting to see anything like that; yet in the traces of the rude and recently evolved ancestors of humanity he would have seen exactly that. It must surely strike him as strange that men so remote from him should be so near, and that beasts so near to him should be so remote. To his simplicity it must seem at least odd that he could not find any trace of the beginning of any arts among any animals. That is the simplest lesson to learn in the cavern of the colored pictures; only it is too simple to be learnt.
It is the simple truth that man does differ from the brutes in kind and not in degree; and the proof of it is here; that it sounds like a truism to say that the most primitive man drew a picture of a monkey and that it sounds like a joke to say that the most intelligent monkey drew a picture of a man. Something of division and disproportion has appeared; and it is unique. Art is the signature of man.
That is the sort of simple truth with which a story of the beginnings ought really to begin. The evolutionist stands staring in the painted cavern at the things that are too large to be seen and too simple to be understood. He tries to deduce all sorts of other indirect and doubtful things from the details of the pictures, because he cannot see the primary significance of the whole; thin and theoretical deductions about the absence of religion or the presence of superstition; about tribal government and hunting and human sacrifice and heaven knows what.
~G.K. Chesterton: The Everlasting Man.
Lascaux cave art from Upper Paleolithic period; c. 15,000 B.C