Excerpt

Taxonomic Space

In order to discuss complications that arise in the understanding of evolutionary processes, it is first necessary to make clear what the evolutionary explanation is to accomplish. For this purpose the concept of taxonomic space is a useful one. We owe this notion to
G. Evelyn Hutchinson, but Walter Fontana and others have since used it in one form or another. This taxonomic space of organisms has a huge number of dimensions, each corresponding to some character that might be used in the characterization of an individual. If one looks at the occupancy of such a space, one is struck by the fact that it has a structure to it. Individual organisms are clustered in the space and those clusters are themselves clustered. And there are clusters of clusters of clusters, rather like the stars in the cosmos. The most important thing for the evolutionist is that nearly the entire space is empty, not only when extant organisms are considered, but when all organisms known to have ever existed are considered. The measure of the emptiness of that space is nearly one, and the measure of the occupancy is nearly zero.

The real problem for the evolutionist is not to explain the kinds of organisms that have actually ever existed. The real problem for the evolutionist is how it is that most kinds of potential and seemingly reasonable organisms have never existed. The problem is to explain the location of the empty spaces in the clustered assemblage of occupied points. It is easy to describe organisms that have never existed. There are snakes that live in the grass, but there are no grass-eating snakes. Birds perch in trees, yet, aside from a few exceptions, they do not eat all that greenery around them but rather spend a great deal of energy searching for food. So why are there virtually no leaf-eating birds? The fact that the measure of the unoccupied space is so big compared to the measure of the occupied space means that explanations of that lack of occupancy are not so easy to come by. That most of the space is empty is expected since the dimensionality is enormous and only a relatively small number of organisms have come into existence since the beginning of life. Since there has only been one history of life, the reason for the low occupancy in the total space is the finiteness of time.

BACK TO Worlds Hidden in Plain Sight