What IS true, MK, is that there is no means of going back beyond history to see if scientific assumptions over large periods of time are true. it s no response to say that a theory is corrected by more theory and calculation. Calculation is a wonderful thing, but if there is an anomaly, an unknown variable anywhere along the way that you don't know about, then the calculation may be off, perhaps even wildly so. That we can observe a constant rate of radioactive decay today tells us nothing about whether it could suddenly and drastically change two hundred years later. That's where predictive science using observations today are useless. We can only test them effectively as far back as historical record goes (with the relability we assign to that), giving us, not millions, or even hundreds of thousands, and not even ten thousand years of a certaintythat can be considered infallible even only for practical purposes. Again, it is a matter of faith to accept the scientific assumptions. I can understand every calculation, every prediction and the basis for it, every method, and I can still see how they can go wrong.
When you express doubt about eyewitness accounts, a number of GKC's observations on those things come to mind, affirming why we do, as a rule, trust them. I do agree that we can, to an extent, hold reasonable doubts about history for the reasons you cite. I merely object to the insistence that we must not doubt current scientific assumptions.
And I don't see anything you say as really dealing with, let alone defeating Chesterton's observations. Especially when he speaks of going by evidence and not by experiment. For the scientist can only experiment in the here and now. There is no time machine to confirm the theory and take us back a million years to observe and experiment. Accepting that there WERE a million years is an act of faith. Not unreasonable faith, but faith, nonetheless.
You are discussing several different things here - not all of which were really related to the text you posted.
First of all - all knowledge is an act of faith. That is really not something that damages the credibility of science any more than it damages my knowledge that I had a muffin for breakfast this morning.
Regarding dating techniques - Certainly it is possible that some change to the nature of the underlying laws of the universe has occurred without us knowing it, and that various radioactive dating techniques are unreliable. Because that is the kind of change that would be required for radioactive dating techniques to behave differently - you see, we understand not just
what happens in those techniques, but also
why it happens in the way it does - those elements are simply obeying the basic laws of physics.
A change in the underlying order of the universe has a host of problems attached to it. It could have occurred last year, and we might not even know it. The stability of the basic laws of nature, whether we understand them or not, is a pre-requisit to all of human knowledge, not just science.
THe other issue is that there are actually many different kinds of dating techniques applied to biological and geological history, not just radioactive dating - many types of dating are used to place events and develop timescales, not just one. There are chemical types of dating, dating based on geological wear and tear or the time it takes for geological events to happen, dating based on tree rings, dating based on light, dating based on relative position of elements, dating based on amino acids, and many others.
So you are suggesting either that all of these techniques have been affected in some way, that they all have at the same time in history gone wrong, and in the same ways. That seems rather incredible.
People think the dating, broadly, is fairly good, not because they have mindlessly gone along with what science gods have told them, but because the weight of evidence is very persuasive, and seems far more probably than other possible conclusions - like the laws of physics have suddenly changed, or three very different sorts of dating have gone wrong at the same time in the same way.
As far as historical observation - I have no problem accepting it is often telling us true things, or partly true things, or it is possible to know of historical events. I would never try and dissuade someone of that. But again, it always comes down to the assessment of probability, having multiple sources, how well the theories fit in with other things that are known more surely. And if you don't know the details, you are simply in no position to make any sort of assessment of those things.
My point was that knowing there are difficulties with historical reliability does absolutely nothing towards making Prof. Pedantic's theory of WWI less likely - you have to look at what he actually says and the evidence. Just like knowing there are limits to the reliability of scientific knowledge does absolutely nothing towards saying that modern cosmological theories or evolutionary theories are wrong - you have to examine the actual theories.
It seems like this is what you have tried to argue here - that the limits of reliability of human knowledge mean that any scientific theories about the past are untenable.
However, what Chesterton seems to make his main point in my reading of this passage was the idea that it is only possible to know facts, not to test theories about them, if they happened in the past, and so there is no way to
Only what can be directly observed can be tested. That is simply untrue. There are tests for such things as I pointed out (and not only in science), and it seems that Chesterton may not have been aware of that. And every time that new evidence from the past comes to light, it acts to reinforce or dispute and theory we have about the past. It is possible to see this has happen on many occasions in the history of science.
Now it is interesting to note that he seems to think that there are very few actual data points for theories about development to consider - that is something that is arguably changed from his period in many cases.
In any case, as Chesterton had no particular issue with the scientific idea of evolution, it is rather funny to see him constantly brought out to beat people who also have no problem with the scientific concept of evolution.