The tragedy of a species becoming unfit for life by over-evolving one ability is not confined to humankind. Thus it is thought, for instance, that certain deer in paleontological times succumbed as they acquired overly-heavy horns. The mutations must be considered blind, they work, are thrown forth, without any contact of interest with their environment. In depressive states, the mind may be seen in the image of such an antler, in all its fantastic splendour pinning its bearer to the ground.
