What is the basis for holding that Uniformitarianism is valid?

I start out this thread having only a hazy notion of Uniformitarianism, (henceforth U). What I understand of it is that the processes which we can observe today occur more or less at the same rate and in the same manner as they have always done and will. As I also understand it, the basis for holding to U is that the observed data backs up the intial presumption. Edit: From msg 61 linked in Percys msg below, U is made up of the following 4 elements:Uniformitarianism, as defined by Lyell, consists of four principles: (I'm not sure to what level each branch of historical science holds to each of these elements. Percy's link (msg 61)indicated that geologists for example, only hold to elements 1 & 2 )Whilst recognising that one may feel one has to start somewhere and if one doesn't it raises questions about what one could tell about the past:Accurate, direct data that indicates processes to have operated according to U is restricted to say the last 100 years or so (although there may be problems with even this). Given the current age of the earth is estimated at 4.5 billion years old, the data only covers 1/45,000,000th of the total amount. Thus, this data represents only a dot on the graph (which is presumed to be a straight line stretching backwards and forwards from this point). This seems, in itself, to be an insufficent basis for saying anything about the validity of U.The comments I have heard thus far (about ice layers and radioactive dating) all seem to suffer from the same weakness, to whit: they all seem to start out with the presumption of U and analyse the data in the light of it. There seems to be a certain amount of wiggling out of this by stating the position as: "We observe and this is what we would expect to see if U was valid - we don't go out with the presumption". Investigating the validity of that approach would, I imagine, be one outworking of this thread.If there was no objective, non-U derived basis for stating U to be valid then how is U stated to be valid? Is U just an arbitary starting point, chosen for philosophical rather than objective reasons? If so, does that mean every conclusion drawn on the basis of U is an arbitary one? In other words, though the puzzle can be arranged in one fashion if U is presumed, could the data not equally fit together with the same level of tentiveness had another arbitary, non-U set of conditions occurred.I don't propose to discuss alternative hypothetical conditions per se - given that if the data has been analysed for so many years in the light of a presumption of U, then no other conditions can hope to compete directly. Not that that is a reason to suppose U is valid. Another outworking of the thread would be discussion around the validity of "authority of the data" argument - should it transpire that all the data is based on an initial, non-objective presumption.This message has been edited by iano, 16-Sep-2005 01:22 PM

Hi Percy,I'll modify the OP to better define current meaning of Uniformitarianism from your link - although I wouldn't be thinking of limiting the discussion to just the geological so perhaps the aspects of uniformitarianism which aren't accepted by geologists are accpeted by other branches in their science. I don't know - but hey, knowledge and understanding through discussion is why I'm here!But before I do that I just want to check on something Having scanned the threads in post 61 and elsewhere, the question still arises in my head. In that post for example, reference was made to a natural nuclear reactor which was said to be 2 billion years old. By analysing various characteristics of it, scientists were able to say that aspects of nuclear reaction are constant over that period of time. But how do they know that the reactor was two billion years old? What did they calibrate the dating instrument against if not one uniformatarianist assumption or anotherThe point of this thread is to find out whether historical sciences have at their foundation a philosophical assumption of what happened in the past or an objective one and if the former, how reliable the sciences based on an arbitarily chosen datum.

Lyell had four principles you say historical sciences don't and never did hold to any of Lyells principles Here they did accept some (any) of Lyells principles (if not all at all times) and presumably still do. Genetic mutation is a mechanism of Toe. It, I gather, holds to a rate of mutation which provides raw material for Survival of the fittest to work on. ToE needs an old enough earth in order for the rate of mutation to have the time necessary for evolution to occur. No old earth, no evolution. How do they avoid any of U's principles?If uniformity of rate isn't held in geology then how are radioactive clocks employed? Is it that different principles are used in different areas and if so, on what basis? How does one chose to decide for uniform rate in one area and non-uniform rate in another?
Surely it can't be the observation which determines it. How can you observe something without a uniformity presumption of whatever sort then presume a uniformity exists on the basis of the observation. Is that not circular reasoning:What I'm trying to get at, but probably not explaining clearly, is that uniformity principles seem to be applied when things appear to be happening uniformly and not when their not apparently happening uniformly. But on what basis does the appearance of uniformity imply actual uniformity?This message has been edited by AdminJar, 09-21-2005 07:38 AM

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Sorry for dissappearing from a thread proposed by me. But I have come across some material from a Christian (on the Wikipedia site) which attempts to explain the scientific basis for the data backing up things like radioactive dating etc (in and of itself - ie: without presumption of uniformity in x,y,z,. Like I said my views aren't set in stone. Will have to read and consider. I might be a little predisposed given that I approached a first scan with the view "lets' see if I can pick holes in this". But if I can't I won'tThanks for the mo...Iano

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