Great, and some have big errors. How do you know how big the error is? Can you compare them to a "correct" clock?
We don't actually have or have to have a correct clock
as we usually think of it since in no case are we really measuring the time of day. What we are measuring is a duration.
We use one clock with a more invariant duration to determine errors in the duration of another. It seems we can also determine the variation in duration of our most accurate clocks but I don't know the details and I'm not sure they are relevant here. At the extremes I think it isn't the variation in durations that produced errors but in how we read out the results and that is understood well enough to put error bars on the readings.
Don't know. I think the best clock is one that is experienced such as counting the number of days by experiencing night and day and making a tally. The person doing the measurements is there at the beginning, middle and end of amount of time measured. This way fluctuations may also be experienced if they occur. Although even here certain faults and assumptions with this. However I don't conclusivly trust any watch that has not been experienced throughout it's whole life.
It sounds like you won't trust any time measurement at all then. So you might as well step out of this debate since it is about a time measurement in the end. (and at the moment about helium diffusion as a measurement method which is known to have a lot of variables that throw it off so you don't trust it at all and can tell slevesque that now).
Since at no time has any one carefully counted time duration for more than years or maybe a few decades you suggest that there are no methods for measuring durations that you will accept. Please be more clear about that.
Personally I wouldn't trust a person ticking off days (or any other interval ) over many of the other methods since I know for a fact that individuals are enormously unreliable at that kind of thing.
Not confident. Clocks that show the same time are more likly to be ones that are in sync with each other, but again not necessarily.
Of course it is true that they are not necessarily in sync. At no time can we have 100 % confidence in any method (including your very weak counting by a person present). However, we are attempting to arrive at what can be considered to be the best conclusion we can some to with the facts at hand. The conclusion may be arrived at with a high degree of confidence or a lower one but it is often still possible to come to a interim conclusion that is somewhat better than "I have no clue."
In the case of the clocks I would give a rather high degree of confidence if all the
types of clocks agreed, very high in fact. Why wouldn't you?
I took this to mean that you were giving me an example of two different methods producing the same result. What is actually contained in the message is many methods giving a wide variety of dates for the minimum age of the earth.
You haven't read far enough. If you do you'll find that the method you like -- counting intervals is used to determine absolute dates and the counting methods agree with radiometric dating methods which also agree with calendar dates given by people who "were there". It is [b]not/b just the minimum dates that are given. It is actual matches between widely varying methods that are the "correlations" being discussed.
If you wish to disagree with this you're going to have to actually read the information supplied. We have months so it isn't a rush. I have reading of my own to do on the helium diffusion method too.
ok, what do you want me to do? Research how normal clocks work and find something that effects them all. What would discussing the finer points of water clocks and pocket watches achieve? If we can't transfer this analogy to natural clocks then what is the point? Yes, some things may impact natural and man-made clocks, but not necessarily. going into the details of how man-made clocks work is not the issue.
The analogy here will carry over to the geological examples we will actually be discussing. Arm waving that there might be something affecting them all to produce the same error doesn't cut it here or there. You don't need to know the details of any of the workings of the clocks to realize there is very, very, very, very unlikely to be something to affect all of them to produce a wrong duration that all agree. That is enough for me to assign a high level of confidence in the conclusion until further facts come in. If it isn't for you; if you require 100 % confidence before you stop saying "We have no clue." then you will
never have a clue.
btw, won't be here this weekend, I'll be back next week
Enjoy the weekend. There is no deadline to all of this (other than I am getting a bit older :S).