otseng wrote:
I find it odd that this assumption would be questioned. Since, SG is
based on the principle (assumption) of uniformity.
"Uniformitarianism is a basic principle of modern geology."
http://en.wikipedia.org/wiki/Uniformita ... science%29
"Uniformitarianism, in the philosophy of science, is the assumption that the natural processes operating in the past are the same as those that can be observed operating in the present."
http://en.allexperts.com/e/u/un/uniform ... nce%29.htm
Bear in mind, I do not subscribe to this assumption. However, it is a basic principle in SG. If you question this assumption, then you question the very foundational presupposition of SG.
What I question is your understanding of uniformitarianism which is very flawed.
We agree that the physical constants have remained the same. So radioactive half-life and speed of light is constant. As for continental drift, that theory has been replaced by plate tectonic theory. Which is not a physical constant, but a theory.
Plate tectonics hasnt necessarily replaced continental drift, but modified it. This idea is generally the same, Im just not a geologist so I dont use the most precise terms.
Again, I would agree with you that climate cannot remain constant. I was simply giving an estimate based on the principle of uniformity. If the assumption of a constant precipitation rate cannot be made to make an estimate, then by what criteria can we judge in how long it took to deposit the ice cap?
Show me somewhere where uniformitarianism says the climate must remain constant? The principal of uniformity NEVER says everything remains constant. Its utterly offensive to me as a scientist for you to make such blatant false accusations.
Stephen Jay Gould's first scientific paper, Is uniformitarianism necessary? (1965), reduced these four interpretations to two, methodological and substantive uniformitarianism[18]. He dismissed the first principle, which asserted spatial and temporal invariance of natural laws, as no longer an issue of debate. He rejected the second as an unjustified limitation on scientific inquiry, as it constrains past geologic rates and conditions to those of the present. Later, Gould expanded on these related propositions in Time's Arrow, Time's Cycle (1987), stating that Lyell conflated two different types of propositions: a pair of methodological assumptions with a pair of substantive hypotheses.[19]
[edit] Methodological assumptions
The methodological assumptions are universally acclaimed by scientists, and embraced by all geologists. Gould further states that these philosophical propositions must be assumed before you can proceed as a scientist doing science. "You cannot go to a rocky outcrop and observe either the constancy of nature's laws or the working of unknown processes. It works the other way around." You first assume these propositions and "then you go to the out crop of rock."[20]
* Uniformity of law: Natural laws are constant across space and time.[21]
The axiom of uniformity of law is necessary in order for scientists to extrapolate inductive inference into the unobservable past. As James Hutton wrote: If the stone, for example, which fell today, were to rise again tomorrow, there would be an end of natural philosophy [i.e. science], our principles would fail, and we would no longer investigate the rules of nature from our observations.[22] In essence, the constancy of natural laws must be assumed in our study of the past, because if we do not, then we cannot meaningfully study the past. Making inferences about the past is wrapped up in the difference between studying the observable present and the unobservable past. In the observable present, induction can be regarded as self-corrective. That is to say, our erroneous beliefs about the observable world can be proven wrong and corrected by other observations. This is Popper's principle of falsifiability. However, past processes are not observable by their very nature. Therefore, in order to come to conclusions about the past, we must assume the invariance of nature's laws.[21]
* Uniformity of process: If a past phenomenon can be understood as the result of a process now acting in time and space, do not invent an extinct or unknown cause as its explanation.[20]
We should try to explain the past by causes now in operation without inventing extra, fancy, or unknown causes, however plausible in logic, if available processes suffice.[20] This is known as the scientific principle of parsimony or Occam's razor.
[edit] Substantive hypotheses
The substantive hypotheses were controversial and, in some cases, accepted by few.[19] These hypotheses are judged true or false on empirical grounds through scientific observation and repeated experimental data. This is in contrast with the previous two philosophical assumptions[20] that come before one can do science and so cannot be tested or falsified by science.
* Uniformity of rate: Change is typically slow, steady, and gradual.[20]
Gould said that mountain ranges or grand canyons are built by accumulation of near insensible changes added up through vast time. Some major events such as floods, earthquakes, and eruptions, do occur. But these catastrophes are strictly local. They neither occurred in the past, nor shall happen in the future, at any greater frequency or extent than they display at present. In particular, the whole earth is never convulsed at once.[23]
* Uniformity of state: Change is evenly distributed throughout space and time.[24]
The uniformity of state hypothesis (i.e. steadystateism) implies that throughout the history of our earth there is no progress in any inexorable direction. The planet has almost always looked and behaved as it does now. Change is continuous, but leads nowhere. The earth is in balance: a dynamic steady state.
