With this post I begin a slightly different format. I have been posting once per week with my comment to Mark, followed by his immediate comment to me. Starting today I’m going to post each comment separately. There will still be one post from each of us per week, so the same pace, but allowing each comment to stand alone for a few days before posting the reply. As you read the close to this one, you will see how far behind the actual communication these posts fall, but be assured they are the actual, unmodified dialog.
Re democracy: In general I prefer to ignore the words other people put into my mouth, but since you return to them, I will reply. I hope this is sufficient to dismiss them. I agree that science is not a “democracy.” Perhaps you would not have concluded that I meant “democracy” by “modern society” if I had said “educated” or “enlightened society.” I was attempting to compare the squelching of alternative views with primitive societies. I will stand by that. As for “balance” (the word from which you move to “journalism”), that was not my word choice, and we have only Gastaldo’s text to suggest that it was my friend’s choice. I do not feel compelled to defend the word, for either way, the intent was to place competing views side-by-side for the sake of debate. I don’t find that to be rare in scientific circles.
Re mistreatment: Perhaps I should have used your word for our treatment, “roughly.” Remember that in both examples we were treated “roughly” for our positions, not our evidence. If any rule of science was broken, it was to dismiss positions without hearing evidence. Evidence was never on the table. It wasn’t allowed.
Re minds only allowing one view: I would say anyone who will not hear evidence for an alternative view by definition only allows one view. If you are open to hearing, and truly considering, an alternative view of the data, then it is a non-issue. Let us proceed.
To get off Square One, I must back up from an assumption you have placed on me. You ask me to “please tell [you] what explanation [I] prefer for that period of evolutionary change.” I do not assume evolutionary change. I see differences between the complexity of organisms below and above the Precambrian-Cambrian demarcation. Evolutionary change is your presupposition for the difference. A person committed to evolution as the only possible explanation will only look at data in order to find HOW the data fits the theory, never asking IF the data fits the theory. If the data cannot be made to fit the theory, then the question is HOW can we tweek the theory to fit the data, never is there a more appropriate theory to fit the data.
So my question is, “What is the most rational explanation for the differences observed between the Precambrian and Cambrian deposits?” The question presupposes nothing about evolution, nor does it set limits on what that explanation might be. I have numbered my logic not necessarily because it is complete or sequential, though to the best of my ability it is, but so that you may refer to my statements by number, should you find objections or leaps in logic.
Every (multi-cellular) body plan found to exist today, plus many that do not are found in Cambrian rock. Depending on how one counts, that come to 30 to 40 phyla compared to today’s 20-30.
This Cambrian variety includes many phyla with eyes, including trilobites, anomalocarid and opabinia. Some trilobites had eye types more complex than found in any fauna today.
Precambrian rock contains almost no multi-cellular organisms (three phyla).
The Precambrian fossil record contains many soft-bodied organisms in great detail, including bacteria, suggesting that there were no developmental stages left out that can be blamed on preservation inadequacies.
The Cambrian is generally considered to have begun around 540 million years ago, with about 10 million years as a window for the end of the Precambrian. Precambrian dates cannot be pushed back further without major conflict with earth cooling and other formation issues.
Possible explanations for the findings:
Darwinian evolution posits that there was a gradual development of all organisms from one or a very few original organisms by naturally selected chance mutations. Darwin recognized that the Cambrian-Precambrian differences were problematic, but expected future fossil discoveries to provide transitional forms. They haven’t. The fossil record shows more distinct fauna in the Cambrian than today, not less.
Stephen Jay Gould’s solution was punctuated equilibrium, for which the main supporting evidence is the lack of support for gradual transformation. (Very rapid evolution, even without a mechanism, had to be his conclusion, because his atheism would not allow him to consider an alternative to evolution. But I agree with you that lack of evidence is not evidence.)
I suggest that without the possibility of time or fossil record to explain the vast differences between the two depositions, known laws of physics do not make chance mutation an option. The most logical explanation for the historical event (or advent) of Cambrian complexity is intentional, outside intervention. Translate that “design.”
Have a great Thanksgiving.