there is no necessary connection between constituents of a series, but there is a necessary connection between all constituents of a system. An additional difference is that in a series there is no necessary layering or hierarchy between constituents of the series, while in a system there necessarily exists layering between constituents of the system. Claiming that visual non-figurative art, or simply, "abstract" art, is not art, made it obligatory for Avital to propose a sound characterization of true art but he found none in the history of aesthetics. After his total disillusionment with aesthetics theory and years of groping in the dark with no solution, Avital decided to look in a completely different direction: to investigate in prehistory how art was born, in the hope that in its fetal stages it would be easier to discern its most basic characteristics. After over twenty years of groping in the dark with no solution, a significant turning point for him was the discovery by Mary Leakey and other researchers who discussed the discovery of a trail of footprints left by hominids in Laetoli, in the north of Tanzania, 3.8 million years ago. These footprints show a remarkable phenomenon: on the path at one time a male, a female and a child walked and the latter, as a game, made sure to step only in the footprints of the male ahead of him, even though his strides were much longer. This paper and about a hundred other papers discussing these footprints treat solely various physiological aspects of these hominids. But for Avital this finding was the key to some insights regarding the cognitive make-up of these hominids and to answer two fundamental questions: the graphic origins of art, as well as the cognitive-structural qualities necessary for something to be a work of art. In his paper "Footprints Literacy: The Origins of Art and Prelude to Science" Avital showed that hominids about four million years ago apparently knew how to read footprints, something no other creature is able to do to this day save humans. Second, he showed why reading of footprints is apparently the origin of painting, as well as the first case where meta-structures of the mind find expression. Thus Avital has anchored the origins and meaning of art in mind itself and in this respect his theory is very different from other well-known theories as those presented by Breuil, Gombrich,