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.
Simon Conway MorrisIf there were a clear prospect that such evils were part of a barbarian past, then at least we might find a small crumb of comfort. No such prospect exists: no scientific analysis can even remotely answer or account for past and present horrors of human behaviour.
Simon Conway MorrisWhen discussing organic evolution the only point of agreement seems to be: ‘It happened.’ Thereafter, there is little consensus, which at first sight must seem rather odd.
Simon Conway MorrisIt is difficult to imagine evolution in alien planets operating in any manner other than Darwinian.
Simon Conway Morris