It's not a Christian website... just a random website with a Creationist writing on something they don't understand very well.
Quote edited for brevity.
Critical Reasoning 101
Welcome to Zosimus’ critical reasoning primer. Since you don’t seem to have the slightest clue about logic and since I am a critical reasoning teacher, I figured I would write this little post to try to help you get a clue of some sort.
Let’s imagine that you’re going to take a test that involves critical reasoning. It may be the GMAT, GRE, LSAT, or another test. It really doesn’t matter. Most of them are structured in a similar way. To start, let’s look at the simplified problem below:
John lives in Chicago. He is 7’ tall (2.13m). Therefore, he must be great at basketball.
The
conclusion above relies on which of the following
assumptions?
When doing a problem such as this one, we should always read the question first. This is important because it tells us what we need to do with the information in the stimulus. The question here tells us two important things: we are looking for an
assumption and the argument has a
conclusion. Therefore, our first goal will be to find the conclusion.
Conclusions generally have the following characteristics:
1. At the end of the stimulus.
2. Contain an
indicator word such as therefore, hence, thus, so, etc.
3. Contain a
modal verb such as must, will, should, can, may, etc.
4. Contain a form of the verb
to be such as be, is, are, was, were, etc.
5. Can pass the
why? test.
As you can probably see, the conclusion of the stimulus is:
John must be great at basketball. This sentence is at the end, contains an indicator word (therefore), contains a modal verb (must), contains a form of the verb to be (be), and can pass the why? test.
What is the why? test? Basically, we should be able to state the conclusion and use other parts of the argument to answer the question why? In this case, we can say:
John must be great at basketball. Why? Because he is 7’ tall.
Accordingly, we see that the why? test not only confirms that we have the right conclusion but also reveals the reason that supports the conclusion. The statement “He is 7’ tall” is a reason that supports the conclusion. If you know something of logic, you may know these reasons by the word premises. Premises are the reasons that are explicitly stated in the stimulus. You may also note that the stimulus contains the sentence “John lives in Chicago.” Does this answer the why? test? No. Accordingly, this is useless information that we do not need to solve the problem.
The argument also relies on
assumptions. For our purposes,
assumptions are reasons that are not stated in the stimulus. Like premises, assumptions can be elicited using the why? test. In this case, the argument relies on two assumptions:
1. Tall people are great at basketball.
2. A person who is 7’ tall is a tall person.
Exact methods for discovering assumptions are out of the scope of this article, but for simplicity sake, I’ll simply point out that the conclusion contains new, surprising words (great at basketball), which are not mentioned in the premise. Thus, an assumption is required as
a kind of a bridge to connect the facts in the premise to the claims in the conclusion.
Perhaps, however, you are skeptical that these two reasons really are assumptions. There is a simple test to determine whether they are assumptions. It is called
the negation test. Basically, if either of the assumptions is negated, the conclusion will be disproved. Let’s try it.
1. Tall people are TERRIBLE at basketball.
Does this statement, if true, disprove the conclusion? Absolutely!
2. A person who is 7’ tall is NOT a tall person.
Does this statement, if true, disprove the conclusion? Without a doubt!
With these principles in mind, let us turn to the post you have made. Your post contains no conclusion—so we’ll have to infer the intent of the author. In this case, I will assume that the author’s conclusion is:
Radiometric dating that produces dates older than 6,000 years is correct most of the time. I think we can determine that this claim,
if true, would effectively require orthodox Christianity to rethink its position on a number of crucial theological points.
Now, I claim that this conclusion (Radiometric dating that produces dates older than 6,000 years is correct most of the time) relies on the assumption that “
The laws of physics did not radically change at the time that Adam ate the forbidden fruit.” How can we determine whether this statement really is an assumption that the argument relies on? That’s right—
the negation test.
So, let’s try negating the assumption to see what happens. The negated form is “
The laws of physics radically changed at the time that Adam ate the forbidden fruit.” Will this statement,
if true, disprove the conclusion? I think it will. Therefore, we have conclusively determined that the statement is an assumption on which radiometric dating is based.
Therefore, it is not possible to use radiometric dating to disprove orthodox Christianity without begging the question
