The long history of mankind is studded with convergences, perhaps most notably in social systems and the use of artefacts and technology. But for hum… - Simon Conway Morris

Gould's arguments on the quirkiness of human intelligence are not only presented as part of an evolutionary argument, but also I believe to buttress an ideological viewpoint. In brief, his assessment of Man as an evolutionary accident is to lead us into a libertarian attitude whereby, by virtue of a cosmic accident, we, and we alone, have no choice but to take responsibility for our own destiny and mould it to our desire.

Convergence is, in my opinion, not only deeply fascinating but, curiously, it is as often overlooked. More importantly, it hints at the existence of a deeper structure to biology. It helps us to delineate a metaphorical map across which evolution must navigate. In this sense the Darwinian mechanisms and the organic substrate we call life are really a search engine to discover particular solutions, including intelligence and—risky thought—perhaps deeper realities?

The underlying reason for convergence seems to be that all organisms are under constant scrutiny of natural selection and are also subject to the constraints of the physical and chemical factors that severely limit the action of all inhabitants of the biosphere. Put simply, convergence shows that in a real world not all things are possible.