Schera, I apologise for not explaining an argument-for-silence and not being as clear as I should be. Often in debate if I talk to a member like Wibble, where we have discussed these things often, I tend to forget that even though he may be clear on what I mean the other posters won't be because at that moment when I am typing, I am so focused on responding to him particularly.
I also get tired of explaining it to Wibble. He likes to use the "show me a human in an earlier layer" argument, as one of his favourite red-herrings, so we as creationists will then try desperately to show him a human in the cretaceous or whatever, him knowing that we don't find one. So it's like someone with a loaded dice with a weight in it saying, "throw a 6 to win".
The reason why it isn't the best argument is because creationists like me, don't accept the evolutionary version of what the rocks mean. We believe all of the rock in the record, represents rock containing limited dead things, and evolutionists believe it is a history of life on earth. Two very different starting points.
So the first point that is most important, that an evolutionist should realise, is that we argue that most if not all of the layers of rock from the various "eons", to us were all created in about one year. This means that if we as creationists find a dinosaur skull in a higher layer such as the Cretacious, rather than the Silurian, that this would not mean anything age-wise, for both the fossil you find in the Silurian and the Cretacious would have been laid down by the flood, in the same year.
The second point you have to consider is that we as creationists don't believe that various eons represent various times on earth but that the general trend or pattern we see, where we find certain types of creatures in certain types of eons, would represent to us, something we call ecological zonation. That just means that we believe that when the flood buried the various organisms, because those burials would have happened in the inundatory stage of the flood, when the super-continent (pangea) was still in place, these patterns we see represent different zones on that super-continent that would have existed in the antediluvian world.
So I hope you can appreciate Schera, that if what the Cambrian, "era" really represents is a large ecological zone that existed 18,000 miles away from human habitation at least in the least farthest direction, that it would be reasonable to suppose that where the remnants of the organisms buried in that zone were now located, might not be anywhere near humans if they happened to be buried, too.
So then I was being sarcastic when I said to Wibble that I don't see a human as a fish, because if the Cambrian era wasn't an era but a niche where particular kinds of marine organisms exist then why would I expect to find a human there? If the Carbiniferous was a swampy, foresty area full of dinosaurs and insects, 15,000 miles away from the nearest human habitation on the super-continent that once existed, would I really expect to find a human in that layer?
Now it's not impossible we will find a human in one of these layers, and there is some evidence to suggest we might have, but it would be very fortunate to find that evidence.
As for an argument-from-silence fallacy it just means this kind of argumentation;
"Haha, you fool, you think grass existed at the time of dinosaurs, there has never been any found with them therefore grass did not exist yet."
Basically that is the argument and it is what Wibble argues - that because we don't find humans in very "old" layers like the Cambrian, it means humans hadn't evolved yet.
The problem is Schera, it is a fallacy because people who argue that argument have been shown so many times that the silence from the fossil record turned out to be nothing. For example they thought mammals evolved after the dinosaurs, but now we do find fossils of mammals with them.
So silence of particular species could mean several things rather than that one thing;
1. The organism might not have existed yet. (if evolutionary eons are true)
2. The organism wasn't buried in that location, randomly. (if the flood is true.)
3. We haven't found that organism yet.
(and any others you can think of Schera, with your good motive to have objective critical thinking skills. )