Stardate 20020226.1318

(On Screen): Some questions are not worth asking, because it's impossible to answer them and the answers would do us no good anyway.

With somewhat less certainty, most scientists think that people who look like us — anatomically modern Homo sapiens — evolved by at least 130,000 years ago from ancestors who had remained in Africa. Their brain had reached today's size. They, too, moved out of Africa and eventually replaced nonmodern human species, notably the Neanderthals in Europe and parts of Asia, and Homo erectus, typified by Java Man and Peking Man fossils in the Far East.

But agreement breaks down completely on the question of when, where and how these anatomically modern humans began to manifest creative and symbolic thinking. That is, when did they become fully human in behavior as well as body? When, and where, was human culture born?

What is "human behavior"? It's not something that happened all at once; it was a gradual process. Where does grey stop being white and become black?

There is a set of hominid footprints preserved in Africa. Three hominids walked across an area which had been covered with volcanic ash, and left their footprints behind, which were then preserved.

One was large, one medium size, one was quite small. The large and medium sized ones are in parallel; one assumes they were walking side by side (because their footprints are in phase). But the small ones are quite remarkable; they follow behind the big one and land inside the footprints left by the big one.

The image which emerges is unavoidable: a man and a woman and a little kid; mom and dad walk side by side, maybe holding hands, and the kid follows behind daddy and tries to step in his footprints. Since a kid's stride length is shorter than a man's, the kid is kind of hopping from foot to foot to lengthen stride. It's something you can imagine a modern family doing in the snow. It's like a little kid putting on daddy's shoes and trying to walk around in them. It's a very human moment.

But these footprints were left there several million years ago; the hominids were Australopithecines. It seems to me that they were already exhibiting "human behavior".