Anyone who says that “the science is settled” is a fool or a charlatan.
That's the first sentence of the post; he's certainly not burying the lede. The professor then walks us through a piece by David Gelertner who credibly argues there is essentially no evidence of evolution creating new species. Gelertner also cites our current understanding of molecular biology and the very large numbers of possible protein combinations: for a protein containing 150 amino acids (the average protein has 250), the odds of creating new useful protein by random mutation is approximately 1 in 10^77. We currently estimate the universe contains 10^80 atoms. When you consider the thousands, or maybe millions, of protein changes that would be required to evolve a new species, and the requirement to do it every time you want to evolve the millions of species on earth, the odds are overwhelming.
I'm not smart enough to propose a theory of how the diversity of living creatures on our planet came to be. But I'm pretty sure Darwinism isn't the answer, and I'm equally sure that seven-thousand-years-ago-god-created-the-earth-and-everything-in-it isn't the answer either. The science is far from settled.
The science is far from settled in many other scientific domains: we had to invent dark matter and dark energy to make our observations of the universe fit with Einstein's theory of general relativity. We don't really know what dark matter and dark energy are, but we need these "weird things" to explain how fast stars orbit around galaxies and why the universe is expanding faster than Einstein's model predicts.
As statistician George Box said, "All models are wrong, but some are useful." Darwinian evolution and general relativity have proven enormously useful. I think our current climate models are wrong, but also useful. I'm wary of anyone who thinks our climate models are good enough to remake entire economies at the cost of trillions of dollars. And I think anyone who says climate science is settled is a fool.