Ediacaran Forms Don't Explain Cambrian Forms

I want to preserve this snippet of an online debate I had for re-use. People seem to think that the presence of Ediacaran forms somehow means they were ancestors or relatives of the Cambrian forms. Despite some inevitable superficial similarities, every time they look at ideas like this in detail they find out the connection cannot be supported by the evidence. Here I answer a post where they tried that, along with the usual "they existed we just don't have fossils". 

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I don't see how any position could be less reasonable than what you are suggesting. Any proposed natural explanation must be accepted over a Divine explanation, even one that fits with the evidence. Why, because we are doing science here? No we are not. We are debating whether something beyond nature, and thus not detectable by science, was involved. Yet here you are, still attempting to impose philosophical naturalism on the terms of the discourse. Nothing seems possible if you a priori refuse to consider it.

Differences in fossilization rates may be a field of study, but we have fossils, even tiny trace fossils, from before. We have fossils of hard stuff and fossils of soft stuff. There was nothing about the earth which prevented fossilization. The obvious conclusion is that fossils were rare before the Cambrian because animals were rare. The Cambrian is thick with fossils. Instead of accepting the evidence you are coming up with hypothesis which contradict all known evidence to explain the absence of the evidence you need to be there. The sample size is the earth. If there are a tiny amount of fossils from the period in question, the obvious conclusion is it wasn't there. Indeed my link provided evidence for the position that the putative ancestors of sponges weren't there, and I can provide similar peer-reviewed studies that make the case for other forms. I doubt it would move you though as your mind appears closed to evidence with dogma predominant.

//The scientific explanations are things that are known to exist and have known properties. If the supernatural were known to exist then maybe, based on the demonstrated properties of the supernatural, we could include it in the conversation too//

The supernatural is known to exist, it just can't be verified by science because science by definition is blind to it even if it does exist. So demanding scientific evidence for the supernatural makes as much sense as demanding supernatural evidence that nature is all that there is. You have stated the truth- you are not willing to include the supernatural in the conversation. I am saying you should open your mind to it.

//You think you have a "gotcha" because scientists are debating whether spriggina was an arthropod or just similar to an arthropod. //

It didn't even have bi-lateral symmetry. We don't even known if it would be classified as an animal, much less an arthropod. It is not a credible arthropod ancestor so talking about superficial similarities is irrelevant.

//They debate whether something they found is a pre-cambrian sponge or some kind of mineral formation or some kind of sponge-like-but-not-exactly-a-sponge kind of organism.//

And I presented a long study that showed in detail why they were mineral formations and their is no good evidence for sponges until the Cambrian. You are acting like these are small differences. One conclusion supports my case strongly and the other yours. I show you studies explaining why a close look at the evidence supports my conclusion and you just go right back to the could-bes as if I had not made my case.

// Kimberella is a candidate for a pre-cambrian chordate ancestor//

No, it isn't. 15 years ago they thought so, but they tested the hypothesis and found it wanting. Here is how WIki puts it..

"These traces, named Radulichnus and Kimberichnus, have been interpreted as circumstantial evidence for the presence of a radula. In conjunction with the univalve shell, this has been taken to indicate Kimberella was a mollusc or very closely related to molluscs.[8] In 2001 and 2007 Fedonkin suggested that the feeding mechanism might be a retractable proboscis with hook-like organs at its end.[11] Kimberella′s feeding apparatus appears to differ significantly from the typical mollusc radula, and this demonstrates that Kimberella is at best a stem-group mollusc.[19] Notably, the scratch marks indicate that the 'teeth' were dragged towards the organism, not pushed away as in molluscs, and that the maximum impact on the sediment was when the mouthpart was furthest from the organism.[20] The direction of grazing is also backwards, as opposed to forwards as in molluscs.[20] Furthermore, the constant width of grooves implies stereoglossy – a trait that is very derived in molluscs.[21] It has been argued that the shape of the feeding traces is incompatible with a radula, and that despite the molluscan body form, the lack of a radula places Kimberella well outside the molluscan crown group.[10] Butterfield points out that plenty of other groups of organisms bear structures capable of making similar marks.[3][22]

Taken together, sceptics doubt that the available evidence is enough to reliably identify Kimberella as a mollusc or near-mollusc, and suggest that it is presumptuous to call it anything more than a "possible" mollusc,[7] or even just a "probable bilaterian".[3]"

//Arkarua is a candidate for a pre-cambrian echinoderm ancestor.//

Again, not a good one. Again, you don't have to go any further than Wiki to know why....

"This identification remains suspect, as the fossils do not appear to have either madreporites, or plates of stereom, a unique crystalline form of calcium carbonate from which echinoderm skeletons are built. These two features are diagnostic of all other echinoderms, as all extinct and extant echinoderms have either one, the other, or both features present.[2]"

//but for you to imply that nothing is known and no fossils have been found and scientists are totally in the dark is purely dishonest.//

Me being dishonest? I didn't imply "nothing is known", my point is that a great deal is known and it all directs to the same conclusion- the Cambrian biota show up suddenly, with great diversity, and no good candidates for their ancestral forms. All pointing to more than nature at work. You keep grasping one straw after another of outdated hypotheses to try and show some way that the evidence points in a different direction and I keep giving one specific fact after another to show why these speculations are incorrect and won't help you.