But we think they can clarify our thinking by leading to useful speculation. The first approach would urge caution in genetic recombination, especially when it comes to germ line manipulations. The second approach suggests a cheery optimism. The cheery, optimistic approach has a lot to recommend it. See how the greenery and the fauna so quickly strive to re-establish themselves.
Science also seems to suggest the cheery, optimistic approach.
It seems we have mutations taking place in us everyday. We are therefore led to the following speculation. Perhaps we can go ahead freely with genetic experimentation relying on nature to take care of itself. Unfortunately however this cheery optimism is too extreme. Mouse-human hybrid cells throw out human chromosomes and so mend themselves.