The development of man and the capacity to act

A few days ago it was in the news that a new ancestor of man has been found, which has been baptized Ardipithecus ramidus. Actually she has been found already in 1994 (in Ethiopia), but it takes always time to analyze and interpret a new find. This Ardipithecus ramidus lived about one million years before our famous ancestor “Lucy”, so about 4.4 million years ago, and she had physical traits that were already typically human rather than apelike. What for philosophers is more interesting, of course, is not which physical capacities this ancestor had but her mental capacities. Could she think as we do? Of course not, but had her thinking already something typical human? And could she act? Surely, she could behave but could she develop already some typical human intentions? In my blog last week I proposed the idea that the difference between behaviour and action is a sliding scale. From that point of view it is likely that the doings of the Ardipithecus ramidus were not merely bodily movements but had already some actionlike traits.
A couple of million years later we see that man makes and uses stone tools. I do not remember when it was. Maybe Lucy already did, maybe it was a couple of hundreds of thousands or a million years later, but already very long ago man made intentionally stone tools. That this man did not simple pick up a stone and used it can be seen from the fact that he went already to places where the stones he needed were found and brought them from there to where he used the tools, a distance of often several kilometres. In short: these ancestors of ours planned what they did.
I think that it is reasonable to guess that man did not have intentions in our sense, so did not take actions in our sense, before she used a language. When did language develop? By chance I have just finished reading a book about the origin of language in man. It defends the theory that it must have been between 200.000 and 50.000 years ago, which is about between the appearance of homo sapiens (modern man) on earth and the famous cave paintings of Lascaux and elsewhere in the world. Moreover, it is likely that the language capacities of man and with it the capacity to execute fully intentional actions developed gradually. In the first homo sapiens the capacity to act intentionally was less well developed than in his descendant that discovered agriculture some 15,000 till 10,000 years ago. Seen it this way, it is likely that these capacities still develop.
What does this mean for action theory? Behaviour and action can be placed on a sliding scale, as we have seen, and the scale can be used for classifying what we do as more actionlike or more like behaviour. In this way, the classification of behaviour and action is synchronic. However, in view of the development of man it must also be possible to classify behaviour and action diachronically: We compare the doings of present man with the doings of our ancestors by placing them somewhere on the sliding scale. By diachronically comparing actions and behaviour of man in this way, we can get insight in human development. Then it is not unlikely that we come to the conclusion that much which is now classified as an action has no equivalent in the past and must necessarily have been more like behaviour (and so necessarily less intentional). Conversely, this may also true for the doings of man in future.