Why is uniformitarianim still taught?

What Percy said. This has been a rather weird thread. I don't think this thread has identified any problems with the teaching or application of geology. The evidence shows that the Earth is very old, and has been formed by processes acting over long periods of time; processes which leave traces we see in the present and which are in many cases still occuring in the present.The word uniformitarianism is nearly always used in the context of the history of geology in the eighteenth and nineteenth century. Modern geology has progressed considerably since those early days, and no longer fits exactly with all the views of the early uniformitarians, but the basic idea that the Earth is shaped continuously by processes in the past as it is being shaped by processes in the present remains foundational; not as an assumption but as a plain conclusion of evidence which has been extensively tested and studied at length. This foundation is not in any rational dispute.Modern geology allows for sudden geological upheavals; but nothing like the global cataclysms involved by the early catastrophists. The catastrophists lost the scientific debate nearly two hundred years ago, because the models they were using do not match the evidence.Cheers -- Sylas

I'll answer this; there is a chance you may hear it better from me.The processes of yesterday are (as holmes suggests) the same kind as those of today; but the speed and intensity varies in different times and places. Why bother to bring up "speed" and "intensity"?Hutton tended to think of constant rates of change; but that extreme form of uniformitarianism is really only of historical interest.By kind, I would mean (and I am sure holmes does as well) nothing about a natural verses supernatural distinction. It would be perfectly possible to bring up a different "kind" of natural process in past; except of course that there is no evidential basis for it. There are a few instances in which we say that we don't know how a certain geological feature arose; but we still look for causes in terms of processes we know. The natural world is sufficiently subtle and complex that known processes can give rise to wholly unexpected results.We do not just "assume" that processes we see now operated in the same way in the past. That is a common distortion made by creationists, and is swiftly cured by any level of exposure to earth sciences. The processes which occur leave identifiable traces, which allow us to actually measure and study processes of the past, and tell the ways in which they may be similar or distinct.Continental drift, for example, was not inferred by watching it in the present and assuming it works in the past. Just the reverse, in fact. It was inferred from traces in the past, and only much later actually measured in the present. The varying rates and directions of motions of land masses can be inferred from studies of the earth. To say they are just "assumed" to operate in the past is a gross misunderstanding of how geology works.This was, arguably, a new kind of process, although still completely natural. Once it was discovered, we still find in this case also that it works now as it did in the past. If you read up on the Wilson cycle, you will find more on modern plate techtonics, involving long cycles operating over many thousands or millions of years. You could think of various stages in that cycle as being a different "kind" of process in the past; but in fact it is all part of a cycle which we see continuing now.You bring up the example of panspermia. The difficulty is that the available evidence indicates very deep levels of relationship between all life, to such a point that panspermia would have to date back so far as to be worthless for helping to illuminate any evolutionary trends.As a model for biogenesis, panspermia is a long shot, wholly lacking in evidence and for which no credible mechanisms exist that make any sense. It is possible that some very simple organic molecules from space might have a role to play in the origins of life; that is an interesting speculation which cannot be ruled out but which does not really solve any of the major theoretical problems for biogenesis. I think you would do well to try learning a bit of geology before speculating. There are plenty of readable descriptions available.Cheers -- Sylas

I'm going to let this one slide. To see my reason for not signing, check out Message 24.Cheers -- Sylas

Actually, I consider that radiometry is a great example; and one of my preferred illustrations to help someone see the errors in what they have been taught by YECs with respect to assumptions about the past in science. Single sound bits don't work; someone who simply gives up immediately an example requires a bit of thought will remain YEC. So let me show how I would use the example of radiometry.YEC routinely state that radiometric dating is based on the assumption of constant decay rates.As CS Lewis notes, a lie becomes much stronger when combined with a bit of truth. This is an example of that principle.The claim of assumed constancy is true, if taken in the sense that the constancy of decay rates is a factor which does not need to be addressed or tested in the analysis of things that could plausibly go wrong with a particular dating study. Reading a scientific paper which applies dating you often see a fairly careful discussion of many potential sources of error in the analysis, usually in terms that fly way over the heads of people who have no familiarity with dating techniques, but it is clear that constancy of decay rates is not something which is even raised as an issue.On the other hand, the term "assumption of constant decay rates" is false in the sense that science in general does not merely make this assumption, but has tested it rigorously at great length. Constancy of decay rates is a conclusion, based on many independent lines of evidence.Observations used to establish the constancy of decay rates, include (but are not limited to):

• Observations of nuclear reactions in distant stars and distant galaxies (for which the reactions took place thousands or millions of years ago).
• Inferences about nuclear processes in the very early universe before galaxy formation.
• Cross checking of dates against other non-radiometric dating methods.
• Cross checking of radically different radiometric methods.
• Study of residues from the Oklo natural nuclear reactor, active nearly two billion years ago.
• Theory of quantum mechanics, which is itself one of the most precisely studied and tested models in physics. Radioactive decay is a process that is well understood. We know a great deal about the relevant forces and the structure of atoms, and how and why they decay. In fact, I would say radioactive decay is substantially better understood than gravity. This illustrates the principal that confidence in scientific models is related also to how well the underlying principals are understood.
• Testing of a range of conditions in which decay might vary. If decay rates have varied, then can we reproduce the conditions under which this occurs? In some cases, yes; and none of them make any difference to dating techniques.

However, the particular way our putative YEC creationist phrases their objection, referring to knowledge built on false foundations, seems to suggest an ever deeper malaise and an almost insurmountable ignorance of how science works. Modern science is not built on flawed foundations in the sense of being called into question by revelation of certain inadequacies in eighteenth century notions of uniformitarianism. When models are disproved, the inferences based on those models must be shown compatible with improved understanding, or else the inferences are gone as well.Cheers -- Sylas