>The main issue is if by tinkering with living organisms one can generate a
>new organism that is totally different, a difference in kind not degree,
>from the original one. If the latter could be accomplished, then that would
>lend credence to the theory of common descend.
What constitutes a difference in kind? New species have been generated, as
has at least one new genus, by tinkering with living organisms.
Actually, the difficulty of such predictions as you are asking for from
evolutionary theory is a lack of data, not a lack in the theory. If I knew
what selective pressures people are going to face and what the
probabilities of various mutations are, I could predict whether we will
evolve the ability to fly. Based on what evidence is available, I think we
are able to avoid such selective pressures by building machines that allow
us to fly. In a closely controlled situation, it is possible to predict
how things will evolve, although the apparently random nature of mutations
and the usual existence of multiple solutions to any given problem make a
definitive (as opposed to probabilistic) prediction nearly impossible. The
same is true of physics. The formulas for gravity are well-known, but
predicting the exact behavior of enough objects over a long enough time
becomes impossible.
David C.