The Germ Theory of Disease is tentative, but it is also settled. No one seriously debates the theory that microorganisms cause infectious disease. A settled theory is one where there is mountains of evidence supporting it and nearly none which stands against it. If new evidence surfaces which falsifies the theory then the theory is tossed, but until that evidence is found it is considered settled.
This has pragmatic value as well. Science progresses by building on top of the work of those who came before you. If you treat all theories as still questionable no matter how much evidence backs it then you can never progress. Also, if a theory is incorrect or not accurate then subsequent work based on the theory can bring that to light.
A good example might be Newtonian gravity. It was considered settled science for a long time, and it still used today to calculate things like the orbits of satellites. However, it was slightly wrong. In cases of extreme velocity or extreme gravity Newtonian gravity gives the wrong answers, and Einstein was able to find a better theory. Now Einstein’s theory is considered settled science for most macroscale phenomena.
There are, of course, religious controversies. But those are not scientific controversies.
I don’t think there are any serious controversies over common descent, unless you want to get into the nit picking about horizonal gene transfer.
Elsewhere, there are disagreements over the role of natural selection and the role of neutral mutations.
I’m not a biologist. It’s not up to me to say whether it is settled. To some extent, declaring it to be settled can be perhaps seen as a rhetorical move. The expression “settled science” does not have a scientific definition.
A review of the scientific literature will find no serious challenges to the theory for decades now. The only controversies are about the fine details of how evolution works. To use another example, there is no serious controversy over the Germ Theory of Disease even if scientists argue over the effectiveness of a specific antibiotic.
The Case Against a Darwinian Origin of Protein Folds
Douglas D. Axe
Four decades ago, several scientists suggested that the impossibility of any evolutionary process sampling anything but a miniscule fraction of the possible protein sequences posed a problem for the evolution of new proteins. This potential problem-the sampling problem -was largely ignored, in part because those who raised it had to rely on guesswork to fill some key gaps in their understanding of proteins. The huge advances since that time call for a careful reassessment of the issue they raised. Focusing specifically on the origin of new protein folds, I argue here that the sampling problem remains. The difficulty stems from the fact that new protein functions, when analyzed at the level of new beneficial phenotypes, typically require multiple new protein folds, which in turn require long stretches of new protein sequence. Two conceivable ways for this not to pose an insurmountable barrier to Darwinian searches exist. One is that protein function might generally be largely indifferent to protein sequence. The other is that relatively simple manipulations of existing genes, such as shuffling of genetic modules, might be able to produce the necessary new folds. I argue that these ideas now stand at odds both with known principles of protein structure and with direct experimental evidence. If this is correct, the sampling problem is here to stay, and we should be looking well outside the Darwinian framework for an adequate explanation of fold origins.
@colewd it depends what you mean by evolution, and I honestly wonder if some of the other responses have overstated the situation somewhat.
There is no significant debate in science right now about common descent of man with the great apes. That is absolutely true. This is settled science right now, and it is notable that none of the creationists groups have engaged with the evidence for human evolution. No real challenge has arisen, and with the rise of genome biology, most the loopholes and circularity in arguments has been removed.
However, there are large debates within evolutionary science right now. Much of it is not settled.
The precise history of large portions of the tree is under constant revision. @jongarvey for example points to the major revision of dinosaur taxonomy. This was a major upheaval and change in our knowledge. That was pretty major, but we are seeing other examples of this all the time.
The precise importance of different mechanisms is subject to a roiling debate now in regards to the Extended Evolutionary Synthesis. What is the Extended Evolutionary Synthesis? I have my opinions about this, but we should be clear that this is a real debate. There are unsettled questions here. Of note, however, the EES is not questioning common descent at all.
Also the value of a “tree” to describe common descent has come under increasing scrutiny. I’ve addressed this before, but there is growing aware ness that common descent does not even predict a tree, as some creationists were smart to realize a long time back (see Walter Remine). The Tangled Tree of Life.
Some of these ongoing debates are merely about emphasis. However, some of them are about deeper questions. That is exactly what we expect in something as complex as biology. There is an immense amount that is unsettled and under constant scrutiny. However, the common descent of man is only growing more certain as we are getting view of more data. That is the key point around which to focus here.
Some people want to look at natural language as a kind of logic calculus. But it isn’t anything like that. Natural languages are full of apparent contradictions and paradoxes. And the languages are all the richer because of that.
Whatever would poets do, if they had to write their poetry in FORTRAN?
This thread has gotten away from me from when I marked it for response. However, when thinking through the philosophy of scientific change, I just read this article from The Atlantic on debates concerning the extinction of the dinosaurs. It is filled with similar tensions that arise with what is being discussed in this thread and others. The key take home, however, is that at some point one simply carries on with their research. We can argue the injustices and the blacklisting and the whatever, but one simply puts their nose to the grindstone and produces. This daily grind is the paradigm shifting essence of science. Systemic mistreatment of Dr. Keller and her work was made right through her perseverance. Science in some insanely broad sense of the word has a way of correcting itself, even in its injustices.
And time will tell which settled sciences become unsettled. shoot, need to run to class!
The first Christians to modify their views of Genesis 1 were the geologists… and I don’t know a more impressive corpus of evidence than what the Geologists have “dug up” (pun intended!).
Physics… chemistry … this isn’t fuzzy-wuzzy biology and capriciously folding protein molecules…
Karl Giberson started off a totally committed Creationist in the mold of Henry Morris! Karl, a true northerner (from Canada), even got a degree from the same school as Henry Morris.
There was just one snag: Karl got his advanced degree in Physics. And even though he taught physics in an evangelical college … the science he was teaching was teaching him. And that’s how he ended up being one of the founders of BioLogos! Maybe it was best that BioLogos didn’t kick off until 2007, a year after Karl’s original inspiration, Henry Morris, had died at age 87?