While the earth remaineth, seedtime and harvest, and cold and heat, and summer and winter, and day and night shall not cease. (Genesis 8:22)
In the origins debate, the young-earth creationist is confronted with the uniformitarian account for the supposed long ages they see in the earth’s crust. “Uniformitarianism is the assumption that the same natural laws and processes that operate in the universe now have always operated in the universe in the past and apply everywhere in the universe. It has included the gradualistic concept that ‘the present is the key to the past’ and is functioning at the same rates.” I appreciate that definition because it clearly states that uniformitarianism is an “assumption,” which differs considerably from a “fact.” Young-earth creationists can agree with uniformitarianism to a small degree based on the biblical perspective provided in the Bible verse above.
I hope I can explain this in a way that makes sense. What uniformitarian thinking does is to look at the geologic processes that are currently taking place (as defined above) and assume that these processes have always taken place at the same rate over millions of years. The uniformitarian, then attempts to mathematically extrapolate back in time to determine the age of the rocks or the formation of strata on the earth’s crust.
In the case of rocks, different radiometric dating methods measure the current rate at which certain minerals within the rocks decay. “Radiometric dating (often called radioactive dating) is a technique used to date materials such as rocks, usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates.” For instance, uranium decays into lead at a certain known rate (“normally”). They can then take a rock containing uranium and measure how much uranium remains compared to the lead, and using currently known decay rates, they can calculate the age of the rock by the ratio of uranium-lead content. Keep in mind that they are “assuming” a constant decay rate.
In the case of sedimentation (or stratification), we can observe river deltas forming. We can observe, for example, that the river is depositing silt onto the delta at the rate of one inch per year. We can then take a core sample of the delta, and we discover that the silt is a mile (5280 ft.) deep. Since we know that silt deposits on the delta at the rate of one inch per year and has done so consistently in the past, we can multiply 5280 ft. by 12 in. and we calculate that the delta is 63,360 years old.
That kind of thinking is what gives us the long ages that evolutionists like to see. However, the problem with that lies in their assumption that things have always been consistent. In the case of the delta, what if the river flooded several times and deposited a foot of silt at every flood apart from the normal 1 inch per year? That would make the delta appear to be older than it really is. Or, what if the coast experiences several storms that erode the delta away? Then the delta would appear to be younger than what it really is.
In the case of radioactive decay, how can the geologist know for sure how much uranium the rock contained to begin with? Or how can they know with certainty that no uranium or lead has been infused into the rock somewhere along the way, or that some event caused greater decay than normal? These things cannot be known so the uniformitarian is left with only assumptions (and they really believe their assumptions).
Young-earth creationists believe the biblical creation account to begin with. Therefore they understand that the earth is probably around 6000 years old but certainly not more than 10,000 years old. They believe the biblical account of the Global Flood and any “uniformity” that is apparent is due to God’s promise that all things would remain consistent (Genesis 8:22 above). From this “ground zero” starting place, they can then make scientific predictions that verify the veracity of the Bible. For instance, the fact that Carbon 14, a highly volatile element having a half-life of only 5,730 +/- 40 years, is still present in petroleum, coal and diamonds. Uniformitarians would not even think to test for C-14 in these minerals, because they assume these minerals to be multimillions of years old, so naturally C-14 should not be present. Young-earth creation scientists believe that the earth is young, so C-14 should be present. So, they look for it, and BEHOLD! There it is!
If you would like to study more on this, the following are some articles from the Institute for Creation Research that may interest you:
The present is not the key to the past – the Bible is!