Radioactive dating basics

Discussion about scientific issues as they relate to God and Christianity including archaeology, origins of life, the universe, intelligent design, evolution, etc.
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#61

Post by BGoodForGoodSake » Fri Aug 04, 2006 8:02 pm

August wrote:
No harm done. Did you see my explanation on deductive vs inductive logic? I think that was one of our unresolved issues from an earlier discussion about the definition of science.
I see where you posted it now.
August wrote:Because deductive arguments are those in which the truth of the conclusion is thought to be completely guaranteed and not just made probable by the truth of the premises, if the argument is a sound one, the truth of the conclusion is "contained within" the truth of the premises; i.e., the conclusion does not go beyond what the truth of the premises implicitly requires. For this reason, deductive arguments are usually limited to inferences that follow from definitions, mathematics and rules of formal logic.

Inductive arguments, on the other hand, can appeal to any consideration that might be thought relevant to the probability of the truth of the conclusion. Inductive arguments, therefore, can take very wide ranging forms, including arguments dealing with statistical data, generalizations from past experience, appeals to signs, evidence or authority, and causal relationships."
Since science is the study of cause and effect, resulting in hypothesis and theories, which in turn are tested and evaluated, but never assumed to be true from the premises (otherwise why test?), science is inductive in nature.
I think you're argument boils down as follows.

You state that deductive reasoning always leads to the truth. And by definition science cannot guarantee the truth, so therefore science cannot be deductive.

But that arises from your definition of a deductive process. There is a more broad definition. Deduction is the process of going from the general to the specific.

Under this definition, this is exactly what science does to formulate predictions/hypothesis from theories. For example, using a theory (from below) to make a prediction.

And induction is the opposite, specific to the general. Using this process we formulate theories. I.e. pulling together many observations to to support a general explanation. Yes scientific theories are arrived at through induction, but this must be constantly tested by making deductions from these theories. The more testable the theory the more valuable it is. In other words the best way to learn is by making mistakes.

Just because we have to test the result of deductive reasoning does not mean its not deduction. It only means that the deduction does not lead to a tautology.

Hah, reading back on the original series of posts I seem to have mixed up induction, deduction, and abduction. I can see why you got frustrated.

Sorry.
=)

That seemed to have taken us away from the main point which was the definition of science and it's relationship to ID.
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#62

Post by August » Sat Aug 05, 2006 6:09 am

BGoodForGoodSake wrote: I think you're argument boils down as follows.

You state that deductive reasoning always leads to the truth. And by definition science cannot guarantee the truth, so therefore science cannot be deductive.
Hang on there, you are already mistaken. I know this sounds like an appeal to authority, but it isn't me that states that with deduction the premises necessarily lead to a true conclusion. It is stated as such in the formal rules of logic, check any reference work on logic or philosophy. This does not mean that all sciences are excluded from using deduction, only those that do not arrive at an absolute answer are.
But that arises from your definition of a deductive process. There is a more broad definition. Deduction is the process of going from the general to the specific.
Nope, not my definition. This cannot mean two things, I encourage you to read further on the topic.

When you say that is going form the general to the specific, that is only partly correct, since the full statement is that using deduction, the conclusion about the particulars necessarily has to follow from the general premises. It does not mean that you can move from a general uncertainty to a specific truth. It means that you go from general truths to specific truths. (I use "truth" very loosely here, a better word escapes me for now.)
Under this definition, this is exactly what science does to formulate predictions/hypothesis from theories. For example, using a theory (from below) to make a prediction.
I think we are still mixing up terms here. Can you please define what a scientific theory is, in your understanding?

Let's see if that can work: The general theory is the premise, so the prediction/hypothesis must necessarily follow as true from the theory. But if the the predictions always confirmed the theory, why do we need to inductively test them to see? Let's go back to your definition of science, that is, science is that which can be subjected to the scientific method. As explained elsewhere before, this definition follows from Baconian inductivism. The general view is that this approach fails, because to arrive at theories from an empirical basis in the first place, one needs to assume certain theoretical preconceptions. To take the specific empirical data, and turn that into a general theory, one must assume that certain unobserved physical conditions apply. That means that the general theory is determined by the assumptions held, and not solely by the empirical data. The method further failed because many sciences were based on indirect and/or unobservable phenomena, like gravity etc.

Newton's reply was hypothetico-deductivism, which is similar to what I think what you are trying to say. Note that this was different to logical deductivism, hence the different name. He argued that one could start with a hypothesis, and through testing, construct a theory.

This also failed....Since there is no way that one can physically examine all the data, it is always possible that some future observations can topple the most established theory. This is what happened with Newtons own theories. Every theory arrived at in this fashion has infinite expected outcomes, which can never all be tested, by definition. This brings us back to where we started, that a theory can be confirmed to some extent, but never conclusively.

The logical argument for this method is:
1. If A, then B.
2. B
3. Therefore A.
Unfortunately, this is not a logically valid argument. It contains the fallacy of affirming the conclusion.
And induction is the opposite, specific to the general. Using this process we formulate theories. I.e. pulling together many observations to to support a general explanation. Yes scientific theories are arrived at through induction, but this must be constantly tested by making deductions from these theories. The more testable the theory the more valuable it is. In other words the best way to learn is by making mistakes.
The concept of testing/falsification came from Popper and still contains all the flaws described in both metods above. I think we never disagreed on the fact that science cannot arrive at absolute conclusions? It seems that while you accept that (if you do), then you are unaware of why that is so. The theory itself cannot make predictions that can be tested, because the empirical consequences of the theory rests on auxiliary assumptions from which predictions and even data collection comes.
Just because we have to test the result of deductive reasoning does not mean its not deduction. It only means that the deduction does not lead to a tautology.
Sorry, no. By definition the conclusion of deductive reasoning is true, because the premises are true. Deduction is necessity, induction is probability. Think of deduction in terms of a mathematical proof. Unless you think proofs are tautologies....With induction, the conclusion may be false even if the premises are true. I don't know how much more or differently I can explain this.
Hah, reading back on the original series of posts I seem to have mixed up induction, deduction, and abduction. I can see why you got frustrated.
No harm. It is a necessary discussion.
That seemed to have taken us away from the main point which was the definition of science and it's relationship to ID.
No, it does not. It clearly has implications on the definition of science. And we can only determine the scientific validity of ID once we have defined science, not true?

(Note: Some ideas here from: Nature and Philosophy of Science: Bridgman)
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#63

Post by BGoodForGoodSake » Sat Aug 05, 2006 8:12 am

August wrote:
BGoodForGoodSake wrote: I think you're argument boils down as follows.

You state that deductive reasoning always leads to the truth. And by definition science cannot guarantee the truth, so therefore science cannot be deductive.
Hang on there, you are already mistaken. I know this sounds like an appeal to authority, but it isn't me that states that with deduction the premises necessarily lead to a true conclusion. It is stated as such in the formal rules of logic, check any reference work on logic or philosophy. This does not mean that all sciences are excluded from using deduction, only those that do not arrive at an absolute answer are.
I understand this. When making a hypothesis the deduction is made assuming that the theory is true. The logical process is the same the only difference is that it is acknowledged (after the deduction has been made) that the original assumptions are falsifiable.
August wrote:
But that arises from your definition of a deductive process. There is a more broad definition. Deduction is the process of going from the general to the specific.
Nope, not my definition. This cannot mean two things, I encourage you to read further on the topic.

When you say that is going form the general to the specific, that is only partly correct, since the full statement is that using deduction, the conclusion about the particulars necessarily has to follow from the general premises. It does not mean that you can move from a general uncertainty to a specific truth. It means that you go from general truths to specific truths. (I use "truth" very loosely here, a better word escapes me for now.)
I think I should have been more specific in my post. The logical process is essentially deduction, in other words the application of deductive reasoning does lead to a true conclusion. The caveat here is if the original assumptions were true. This it were not a deductive conclusion it could not test the assumptions. In other words if the deductive conclusion(hypothesis) is false the premise must also be false. What I meant to say is that just because the deductive conclusion can be falsified does not mean that the hypothesis is not a result of deductive logic.
August wrote:
Under this definition, this is exactly what science does to formulate predictions/hypothesis from theories. For example, using a theory (from below) to make a prediction.
I think we are still mixing up terms here. Can you please define what a scientific theory is, in your understanding?
It is an inductive conclusion based on observations.
August wrote:Let's see if that can work: The general theory is the premise, so the prediction/hypothesis must necessarily follow as true from the theory. But if the the predictions always confirmed the theory, why do we need to inductively test them to see? Let's go back to your definition of science, that is, science is that which can be subjected to the scientific method. As explained elsewhere before, this definition follows from Baconian inductivism. The general view is that this approach fails, because to arrive at theories from an empirical basis in the first place, one needs to assume certain theoretical preconceptions. To take the specific empirical data, and turn that into a general theory, one must assume that certain unobserved physical conditions apply. That means that the general theory is determined by the assumptions held, and not solely by the empirical data. The method further failed because many sciences were based on indirect and/or unobservable phenomena, like gravity etc.
What is your definition of failed?
August wrote:Newton's reply was hypothetico-deductivism, which is similar to what I think what you are trying to say. Note that this was different to logical deductivism, hence the different name. He argued that one could start with a hypothesis, and through testing, construct a theory.

This also failed....Since there is no way that one can physically examine all the data, it is always possible that some future observations can topple the most established theory. This is what happened with Newtons own theories. Every theory arrived at in this fashion has infinite expected outcomes, which can never all be tested, by definition. This brings us back to where we started, that a theory can be confirmed to some extent, but never conclusively.
Right never conclusively, science is always open-ended.
August wrote:The logical argument for this method is:
1. If A, then B.
2. B
3. Therefore A.
Unfortunately, this is not a logically valid argument. It contains the fallacy of affirming the conclusion.
No this is incorrect, it is as follows.
1. If A, then B
2. ~B
3. Therefore ~A.
August wrote:
And induction is the opposite, specific to the general. Using this process we formulate theories. I.e. pulling together many observations to to support a general explanation. Yes scientific theories are arrived at through induction, but this must be constantly tested by making deductions from these theories. The more testable the theory the more valuable it is. In other words the best way to learn is by making mistakes.
The concept of testing/falsification came from Popper and still contains all the flaws described in both metods above. I think we never disagreed on the fact that science cannot arrive at absolute conclusions? It seems that while you accept that (if you do), then you are unaware of why that is so. The theory itself cannot make predictions that can be tested, because the empirical consequences of the theory rests on auxiliary assumptions from which predictions and even data collection comes.
No the empirical consequences of the theory comes from the ability to test conclusions, reached by deduction, from the assumption, that the theory is correct. As you can see from the logical statement above a theory can be tested. We can only verify that a theory is false.
August wrote:
Just because we have to test the result of deductive reasoning does not mean its not deduction. It only means that the deduction does not lead to a tautology.
Sorry, no. By definition the conclusion of deductive reasoning is true, because the premises are true. Deduction is necessity, induction is probability. Think of deduction in terms of a mathematical proof. Unless you think proofs are tautologies....With induction, the conclusion may be false even if the premises are true. I don't know how much more or differently I can explain this.
I understand this quite well. What I don't think you seem to be grasping is that by using deduction and then falsifying the conclusion it is possible to falsify the original assumption. In this way all assumptions are assumed to be just that and are subject to falsification.

(And please don't tell me that I cannot assume that assumptions are falsifiable becase then this assumption is also falsifiable.)
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#64

Post by August » Sat Aug 05, 2006 11:32 am

Oy, it seems as if you want to redefine things for your own purposes. I will attempt to explain this again, but I will respectfully ask you to please go and read some of the history and philosophy of science, including formal logic. I can tell you that there is no philosopher of science that I have seen that agrees with you that deduction is widely used doing science.

Let's try this again.
BGoodForGoodSake wrote:I understand this. When making a hypothesis the deduction is made assuming that the theory is true. The logical process is the same the only difference is that it is acknowledged (after the deduction has been made) that the original assumptions are falsifiable.
I am not sure you do understand this. You know the form of logical reasoning is a syllogism. In its simplest form:
1. Major Premise
2. Minor Premise
3. Conclusion

According to your reasoning, you are taking the general theory, and assume that it is true, and that becomes your major premise. However, the whole reason for entering the argument in the first place is because the theory is uncertain, otherwise why do it? You are trying to support your theory, but cannot absolutely prove it, as described below. By definition, that process is described as inductive reasoning, not deductive reasoning, and you said it in your last sentence, it contains uncertainty as to the validity of the premise and therefore the conclusion. When you talk about uncertainty in this fashion it relates to induction, not deduction. And this is exactly the problem that Newton ran into with his hypothetico deduction method. Read on:
August wrote:
The logical argument for this method is:
1. If A, then B.
2. B
3. Therefore A.
Unfortunately, this is not a logically valid argument. It contains the fallacy of affirming the conclusion.
No this is incorrect, it is as follows.
1. If A, then B
2. ~B
3. Therefore ~A.
Not quite.

Let's substitute: T= the theory and D=the data set that is expected if the theory is true. You would then have, according to your reasoning:
1. If T, then D. (If the theory T is true, then, we will see the data set D)
2. D (We measure/observe/confirm the data set D)
3. Therefore T (The theory is confirmed as true)

This is exactly what you have been describing all along. We take the theory, then we test it by measuring, and through that we confirm whether the theory holds true or not. This is not a valid logical argument, it commits the fallacy of confirming the consequent. The valid logical form is:
(This is the Modus Ponens form of the argument.)
1. If T then D.
2. T
3. Therefore D
This is invalid in the world of science, since you have not proven either D or T to be true. T is the result of an inductive process, by your definition, while you cannot ever conclusively arrive at D without measuring all the data related to the theory everywhere. Also, there may be other explanations for D, other than T.

You correctly stated the Modus Tollens form of the argument:
1. If T then D
2. ~D
3. Therefore ~T
Similarly, what makes this invalid in the case of science is that you cannot empirically verify ~D, unless you measure all data relating to the theory everywhere. You cannot logically and absolutely say that ~T is true, since you have not conclusively proven ~D. Also, read below on the Duhem-Quine problem.

So, back to inductive and deductive reasoning. From the above, we can say in science that in either form of the argument we see a subset of dataset, but it is never complete, so the best we can do is say that it is a good approximation of the data we expect to see under normal conditions everywhere. Then, since we cannot with certainty say that D is true, and we arrived at T through inductive reasoning as well, there is no way that it constitutes a deductive argument, it is inductive all the way, otherwise it is logically fallacious.
No the empirical consequences of the theory comes from the ability to test conclusions, reached by deduction, from the assumption, that the theory is correct. As you can see from the logical statement above a theory can be tested. We can only verify that a theory is false.
Nope, that is wrong, as demonstrated above. But I think you misunderstood what I said.

If what you say holds true, then no theory can ever be even approximately true, because one will never dismiss the theory, one will just dismiss just one of the primiary or auxiliary assumptions. Sure a theory can be tested, but to test the theory you need to assume as true a whole lot of other things from outside the theory. The dependence on background assumptions is called the Duhem-Quine thesis:
"Any experiment taken to disprove an hypothesis can be rendered compatible with that hypothesis by denying instead an "auxiliary assumption.
Thus, individual hypotheses cannot be disproven."

Following, then empirical consequences of the theory depends on those outside assumptions as well, and you cannot conclusively falsify (or prove) the theory without proving or disproving the assumptions too. You can only test the whole package of theory and auxiliary assumptions. If we have reason to believe that the background assumptions are acceptable, i.e. we assume them, then we can rationally, if inconclusively, arrive at a theory that is confirmed or disproven depending on the empirical test.
I understand this quite well. What I don't think you seem to be grasping is that by using deduction and then falsifying the conclusion it is possible to falsify the original assumption. In this way all assumptions are assumed to be just that and are subject to falsification.
Uh, ok, wait. I be lost. So what you are saying is that we are going to assume that all the assumptions are assumed, then through the process of deduction, we are going confirm that we assumed our assumptions?

Also, you are not necessarily falsifying the original assumption if you refer back to the Modus Tollens argument above, it is just "maybe" falsified. Unless you measured all the data, everywhere...otherwise it is an inductive argument and not a deductive one.
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#65

Post by BGoodForGoodSake » Sat Aug 05, 2006 3:35 pm

August wrote:Oy, it seems as if you want to redefine things for your own purposes. I will attempt to explain this again, but I will respectfully ask you to please go and read some of the history and philosophy of science, including formal logic. I can tell you that there is no philosopher of science that I have seen that agrees with you that deduction is widely used doing science.
Sorry I don't really have a clue what you are trying to say. lets use an analogy.

Here's a theory

T:All red cats have bells.

Heres a hypothesis deduced from this theory.
Twinkles the class pet is a cat.
Twinkles is red.
Bells make ringing noises.
H: Therefore Twinkles must make a ringing noise if you were to shake him.

T -> H

We shake twinkle and he makes no sound but a meow, therefore H is false.

~H Therefore ~T

See? We assumed the theory to be true, reached a hypothesis through deduction. Then we went and disproved the hypothesis. Because it was a conclusion based on deductive reasoning it was guaranteed to be true IF AND ONLY IF the theory is true. Using the Modus Tollens form of the argument we have disproven the theory.

So what method was used to reach the hypothesis?

However, I will agree with you that science is mostly an inductive excersize.
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#66

Post by Felgar » Sat Aug 05, 2006 8:14 pm

BGoodForGoodSake wrote:Because it was a conclusion based on deductive reasoning it was guaranteed to be true IF AND ONLY IF the theory is true. Using the Modus Tollens form of the argument we have disproven the theory.
This is correct. Remember that the statement A->B may or may not be true in and of itself. Only if we know it to be true, can we begin to evaluate the truth of A and B in relation to one another.

If the statement A implies B is true, then it is not possible for B to be false when A is true; this should be intuitive. Therefore, IF B is false, then A must also be false, and if A isn't false while B is false then the original statement is incorrect. Therefore as properly demonstrated by BGood, the two statements (A->B) and (~A or B) are logicially equivalent.

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Re: Radioactive dating basics

#67

Post by sandy_mcd » Mon Aug 07, 2006 9:22 pm

The blue coloring is very misleading in the squares at the top of the figure. The number of atoms is the number of black dots which is not at all proportional to the area colored blue.

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Re: Radioactive dating basics

#68

Post by sandy_mcd » Mon Aug 07, 2006 9:30 pm

dad wrote:So, there is a process of decay we can measure. It is known. It produces a daughter element. As long as the present state of decay existed, it can be assumed it worked the same.

How long did it exist? That is the question. I say about 4400 years. Before that, the spiritual and physical state (rather than the physical only present state) saw no decay universally.

If we look at the daughter now, the only portion of that material that was produced by decay was the bits since the split, which left us in this physical only state. Therefore, the daughter in no way can be used under any circumstances to measure age beyond the split!
So you are saying:
1) radioactive atoms did not decay until 4400 years ago.
2) at 4400 years ago at the split, radioactive elements started to decay at their current rate.

If this is an accurate representation of your model, then nothing would radiodate to older than 4400 years ago. Yet many objects radiodate to far older than 4400 years ago. How is this discrepancy accounted for?

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Re: Radioactive dating basics

#69

Post by dad » Fri Aug 18, 2006 11:25 am

sandy_mcd wrote:
The blue coloring is very misleading in the squares at the top of the figure. The number of atoms is the number of black dots which is not at all proportional to the area colored blue.
Guess this university should use better grapics you might like more then.
http://www.stmarys.ca/

But it serves fine as a simple illustration, not meant to be rocket science. Do you have a specific point as to how that might affect the overall concept discussed here?

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Re: Radioactive dating basics

#70

Post by dad » Fri Aug 18, 2006 11:30 am

sandy_mcd wrote: So you are saying:
1) radioactive atoms did not decay until 4400 years ago.
2) at 4400 years ago at the split, radioactive elements started to decay at their current rate.
AS best as I can so far determine, I can't see any other way. Yes.
If this is an accurate representation of your model, then nothing would radiodate to older than 4400 years ago.
Ha. Nothing does! In claiming it does, it depends on unprovable assumptions of a same past.
Yet many objects radiodate to far older than 4400 years ago. How is this discrepancy accounted for?
It is simply that the people so called dating things assume a same past. For example they assume that the present decay was always in effect, and produced the daughter materials (as indeed, they NOW do produce). In reality, in a different past, the daughters would be there already, involved in some other process, not of decay.

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