Gman wrote:
But true scientific hypothesis must be falsifiable. Can ID be falsifiable? ID is actually quite open to falsification. If we use evolution to falsify ID, all a scientist needs to do is take a bacterium without a flagellum or knock the genes out within the bacterium flagellum, then go to a lab and try to grow the bug for a long time to see if it produces anything resembling a flagellum. If it produces a flagellum, then ID would be proven false on the general grounds that the scientist didn't invoke intelligent causes when purely natural causes would suffice. But let's turn that around, how do we falsify the contention that natural selection produced the bacterium flagellum?
This kind of thing has been done - I'm can't recall which piece of research it was off the top of my head but it essentially went like this:
- Take some cells that feed mainly on a particular food source - glucose, say.
- Remove or otherwise alter the genes for glucose digestion so that the next generation of cells are unable to feed on it
- Breed a number of lines of the impaired cells, and allow each line to propogate for a number of generations in a glucose-rich environment.
The outcome was that some or all of the lines of cells regained the ability to digest glucose, and in manners different from each other and from the original culture (that which had its genome altered).
Similar things have been observed but in a "bottom-down" manner, that is seeing a trait that wasn't present in previous generations emerge in later ones (as opposed to altering genes and waiting for a trait to re-emerge); for example the ability to metabolize citrate seen in Lenski's experiments, and to metabolize nylon in "wild" bacteria.
My point is that none of the above falsifies the ID hypothesis; it may weight things totally or partially against certain flavours of designers, but we can certainly conceive of a designer capable crafting DNA such that it was able to handle such situations.
A question for you all more out of curiosity that anything else - do you believe that the evolution of, say, flagella, or of apes to men is in impossible in principle, or that it just hasn't happened in practice? That is to say, do you think that god created everything pretty much as we see it, but that potentially species could go on to evolve?
To lay this out more orderly:
- All the information needed to turn a single cell into a creature is held in nothing more than the sequence of nucleotides in that cell's DNA (you probably all agree here)
- DNA can mutate in a number of different ways, and mutations are carried forward throughout generations (you probably all agree here, too)
- Mutations can be responsible for new protein sequences, sometimes manifesting itself in the phenotype (I'm guessing you all agree here as well)
In light of that I can think of a few possible outcomes - feel free to say if you agree with any of them, or to suggest more:
a) DNA physically cannot mutate enough to change one species into another - something in DNA itself impedes such mutation
b) DNA physically cannot mutate enough to change one species into another - some factor external to DNA impedes such mutation
c) DNA could, in principle, mutate enough to change one species into another - it just hasn't ever happened
d) DNA could, in principle, mutate enough to change one species into another - but some factor prevents it from doing so