It is the scientific interpretation - not the data - that involve unverifiable assumptions and guesswork. All of science is subject to this limitation, though there are (from what I have learned) two general categories in this regard.
I apologize for taking so long in my response. Upon returning to college there was a period in the beginning of the semester where the internet doesn't want to cooperate.
First, science in general relies upon several assumptions without which science could not operate. Among these are the following: 1) an intelligible, logically ordered universe; 2) consistent, uniform 'rules' governing the operation of the universe; 3) that our senses give us a reliable 'window' on reality; 4) that our human mind is capable of processing the information provided by our senses. These assumptions might seem to be 'givens', but it's not that simple.
I agree with all but 1. While a logically ordered universe would make scientists lives much more easier, it doesn't have to be in order to pursue knowledge through the scientific method. And as we (humans) are designed to think logically, we tend to order things and concepts logically and with a defined order that is, well, logical.
A Christian worldview, for instance, provides a solid rationale & explanation for why the universe is like this. Among the premises of Christianity is that 1) God is a rational, moral being; 2) that He created man in his image, which entails rationality and morality; 3) that He created the universe in general and the earth in particular as a home for man; and 4) that He commanded man to 'subdue' [bring under his dominion] the earth. The preceding 4 biblical premises directly and fully justify the 4 assumptions that underpin science listed above.
I agree, but I'm not sure how 4 justifies any of the underlying assumptions of science.
In fact, only the bible provides a solid rationale for the scientific enterprise and this is precisely why modern science was launched in Christian Europe largely by Christians It is also the reason science could never get a foothold in countries like China or the Islamic world; these cultures/religions lacked the necessary philosophical framework to provide a firm foundation for science. The same is true of atheism, as it too lacks the framework to undergird and justify the scientific enterprise.
Now here I must protest. The modern foundations of science were indeed built by Christians, but they were only able to do so through the pre-knowledge kept by the Middle East during the dark ages of Christian Europe. Which ultimately came from Rome and Greece.
I almost see the world advancing in knowledge by different countries/cultures passing on the piton of knowledge to different countries/cultures; similar to how the great powers of the world change over time. For example the U.S. basically took the knowledge of Europe and added onto it becoming the super power it is today and in the past. Now the U.S. is decreasing in power and it looks like China is going to rise up in a new global/international economy. I don't think any country/culture is inherently lacking a framework to understand science, or to get there, but due to other factors in the world, the great safe haven of knowledge is constantly changing.
I think, even when talking about humans devoid of religion, we can come to the conclusions necessary to implement scientific thinking, inquiry, discovery and understanding beyond any reasonable doubt.
This makes it all the more galling when evolutionists prattle on about the war between religion and science and how they, as atheists, are more rational and refrain from superstition. All of this has long been known and many scholars of the history of science have contributed to this thesis. Among them are Rodney Stark, Toby Huff and Peter Harrison.
Religion has made some very important contributions to science, same with philosophy. But as science progresses many of these things that once nurtured it is now snaring it; suffocating the life out of it. The right balance between science and religion must be found, and the right balance seems to change over time; both as a philosophical framework and in a pragmatic way. Now it looks like religion needs to back off of science, so science can reach its full potential in an objective way, free from religious influence. That is one of my main reasons for participating in the evo-creo debate; I see creationism as crossing the line and tainting science in the public schools.
Second, and to answer your question, is the category of the historical sciences. These include origins science, archeology and forensics. I would also include much (but not all) of astronomy - especially cosmology since given the distances involved, we are actually 'looking back into the past' when we gaze through a telescope. Here, assumptions play a more direct and visible role. Many times, the subject under investigation is a historical singularity - what happened only happened once and in a particular way. We cannot repeat history in the lab. Even if we manage to recreate a given phenomenon, there is no way to prove that it happened in that particular way regarding what is being examined.
Technically I think we see everything in the past, as light does have a speed and there is distance between our eyes and anything we see, but point taken. I suppose that the biggest assumption in astronomy is that the same rules apply here as well as everywhere. And while we can't recreate a big bang from a singularity, we can definitely observe the effects, making it a part of scientific inquiry.
As to how this relates to the age of the earth, take radioactive dating. We have a chunk of igneous rock that we want to date with, say, the Potassium-Argon (K-Ar) method. This involves measuring the ratio of parent isotope (potassium) to daughter isotope (argon) and then calculating how long it would have taken the potassium to have decayed into argon given the known half-life of potassium. Seems pretty straight-forward - until you think about it for a minute. What assumptions are involved in this determination? 1) that the decay rate has been constant throughout history; 2) that the rock in question was a 'closed system' throughout its entire history (no leeching, no contamination by addition of exogenous parent or daughter isotope, etc.); 3) that the ratio of parent-to-daughter isotopes at the rocks creation can be known. All of these assumptions bear directly on the credibility of radioactively determined dates.
I'm hesitant to comment, with geology, radiometric dating is not something I'm really familiar with. As far as 1 is concerned, the rate of decay is consistent as far as we know. Under intense physical and chemical environments, the rate of decay cannot be changed. So unless we impose different laws for different times, I don't see 1 as strong evidence against it. For 2, if I remember correctly (please don't hesitate to correct me) once the rock is formed it will not get contaminated to the point that inaccurate results will form, meaning that scientists know when they see a contaminated part that isn't part of the original rock. So the contamination must happen during the rocks formation. For 3, this is something that I myself have asked other evolutionists before. I hate cop outs, but there's not much else I can say about it other than I've been told that you don't need to know the original ratio to find the age. I wish I knew more, as I'm sure I'm missing something.
There is simply no means at all to make confident determinations of points 2 & 3 - especially point 3. In fact, the literature is littered with dates being rejected or modified because they didn't fit with evolutionarily determined expectations. Common excuses are that the rock was 'reworked' or 'reset' (fully or partially) by subsequent melting, there is 'excess argon' giving an anomalously old date, and others. Point 1 is a bit more amenable to scientific investigation since, if decay rates were different in the past, there should be evidence consistent with that hypothesis. The was the main focus of the RATE project and they did find such evidence (helium retention, polonium halos, etc.)
From what I've read from the RATE team, they found some anomalies regarding radiometric dating, but those anomalies are in no way enough to disprove the basic outline mainstream science has put forth.
Now, as to the comparison between interpreting 1) propositional statements and 2) scientific data. There are fewer assumptions, at a foundational level, when it comes to interpreting language vs. scientific data. First, the very purpose of language is to communicate ideas and concepts. We have a very good knowledge of the grammar, syntax, word usage history and culture of, for instance, the Hebrew and the Greek languages. We know the distinctive characteristics that distinguish Hebrew poetry for Hebrew historical narrative, for example. This knowledge gives us a very good handle on interpreting ancient texts despite the fact that here are difficulties with obscure words or sentence construction here and there.
In contrast scientific data is 'stuff'; it is just 'there'. It doesn't 'say' anything; the data means nothing if not placed in the context of an overarching framework. A good example is the redshift of starlight. The data is the magnitude of the redshift - that's it. This data is interpreted as the recession of the stars/galaxies due mostly to the expansion of space. The redshift doesn't 'say' that directly, it has to be interpreted in the framework of modern cosmology to yield that conclusion. And it's not the only way the redshifts can be understood, either. Halton Arp - no creationist he - has made the case that a great many of these redshifts are intrinsic and not indicative of distance.
Interesting stuff on red-shift, but astronomers don't use red-shift do determine distance though, just the radial velocity of the object. In fact, redshift is a good example of how new data influences/changes the existing paradigm of the day. Before we really looked at the redshift of galaxies many were in the steady state theory mindset, when we realized that things were going away from us, we were able to conclude a singularity at some point in the distant past. Either way, I suppose the data must be interpreted into a model if we are to use that data. But from what I've seen of scientific interpretation, it flows logically and I see no reason to discount the 'interpretation' as it is based off of the data.
Finally, consider the history of science; it is littered with revolutions. Paradigms are turned inside out, upside down and thrown on the garbage heap by as little as a single observation. Scientific textbooks today are constantly revised in light of new evidence; a textbook from the 1950s would be largely obsolete today. Nature, practically speaking, is infinite; we will never know even close to everything about nature. There will always be more unknowns than knowns; thus the potential for radical revisions of our understanding. Language, on the other hand, is a much more limited arena. There are far fewer unknowns in language than there are in science and thus far fewer assumptions.
Revolutions are necessary to the progress of science, and we will never know everything there is to know about the nature of the universe, but that doesn't mean we can't get close to understanding how the universe functions and operates on the laws and properties it possesses.
This is why I say that interpreting propositional statements is simpler and employs fewer assumptions than does historical science.
On the surface I agree, but once studied, both can be accepted beyond reasonable doubt.