Criticizing bad science.
No, Dr. Cannara, nature is not stupid, but what you're claiming...well.
Let's dig in.
The video is highly edited, it appears, and so perhaps some reasonable stuff got edited out.
He says that there are organisms which can survive a thousand times more radiation than humans. Ok, but we're human.
He's correct, cells do have the ability to repair themselves (unless they die), but the repair processes are not perfect. This FACT leads us to recognize that there is a risk of misrepair, and this risk can be translated into a risk of cancer in somatic cells or a risk of inherited effects associated with sex cells.
We've evolved into humans because DNA is mutable. Any early life which wasn't mutable (if it existed at all), wouldn't have had a means of evolving in order to cope with changing environmental conditions. Not only are your cells constantly repairing themselves (like Cannara says), but they are also constantly accumulating mutations (which he doesn't say).
He briefly mentions oxidative damage (cell metabolism results in oxidants which can damage the cell), but most of that occurs in the mitochondria, not in the cell nucleus where the nuclear DNA is. The mitochondria are the cells' power plants, which supply the cell with energy via cellular respiration. The mitochondria also have their own DNA, referred to as mtDNA in order to highlight the physical difference.
It's hilarious that he presents a slide (about 1:35) which shows that if the DNA is not repaired, the result is cancer! His slide refutes his point and supports what I wrote above...you just can't make this stuff up!
And you just knew it was coming....there's natural radioactivity, hence, (cough, wink) radioactivity is good for you! We see analogous propaganda with other science deniers (CO2, UV radiation, etc.).
Next comes the health physics version of the Wellian Haeckel's Embryos (see my page "Comparing The Creationist and Hormesis Cults", above right). Haeckel was a nineteenth century illustrator who drew pictures comparing the embryos of different species. The illustrations were a bit off, but no one knows if it was intentional, accidental, or simply the best he could do. Johnathon Wells (also a Moonie) claims that evolutionary biology isn't true. Why? Because of those old drawings. How ridiculous is that?
Cannara (via Calabrese, see that Cult comparison page) is pulling essentially the same stunt with Muller's old Nobel Prize acceptance speech. No one today integrates Muller's speech into their conclusions for LNT, any more than anyone today integrates Haeckel's work in their understanding of biology. And no one knows what was in Muller's head at the time.
Cannara mentions Christopher Busby, who is a health physics denier of the opposite stripe (a fear monger as opposed to a hormesis propagandist). I've criticized him many times (search his name within the blog).
Music, please Maestro: