So what? It is consistent with the facts. Also, each of the mechanical elements of the overall theory are testable. It remains a valid scientific theory, because of that.
Re:The "screed" as you call it.
"Evolution is not an isolated concept that can be expediently omitted from a high-school biology syllabus. Rather, it is the single unifying concept of modern biology. It unites all areas of biology, from ecology to physiology to biochemistry and beyond. Without it, students are denied a framework to understand how these different areas are related and interdependent. "
Other than the use of the word unify, it's basically true. It is a theory that consists of a set of minor theories and hypothesis that provide an overall understanding of how present life forms got here. The "unity" signifies only that it's interdisciplinary. There is no faith here and it is not a religion.
"Biology, like all sciences, is a system of testing facts or concepts."
Biology is a scientific discipline that focuses on all direct aspects of life. It is a body of knowledge, a subset of science. The scientific method is a system for testing facts and concepts.
I am not sure how you would test the theory that macro changes (offspring of gill breathers having lungs, by mutation) are possible.
But let's not quibble, I agree with most of what you say. Evolution is a theory, it is scientific to the extent that it is testable, I understand what you mean by "it is a valid scientific theory" and I agree with what you mean.
The common useage, however is "valid scientific theory" = "true", which leads to statements like the one I quoted from the Yale grad student.
If macro evolution did not occur, the essence of biology would not change one whit, which was my point.
Not really. Not at all.
You might read Not by Chance for a discussion of the probabilities involved. I remember being taught in college that there is a small probabililty that when you release a stone, it will go up. But one ought not to expect such a result. Spetner essentially shows that stones should be falling up all over the place by comparison with the probabilities that any macroevolution actually occurred. (my characterization)
It's not consistent with our notion of chromosome pairs either. We have 23 pairs. It's pretty hard to evolve "gradually over a long time" from 22 (or 24).
ML/NJ