We're constantly bombarded with radiation by simply living. We wouldn't make it to adult hood if all DNA damage was lethal. DNA damage is more likely to be repairable or outright kill a cell than cause cancer, just by pure numbers.

> Chemotherapy is just "let's kill enough percentage of this guys cells to kill the cancer cells before they kill him."

That's exactly what I said with "otherwise indiscriminate treatments." Our body is not a homogenous mass of one type of cell; different cells react differently. If cancer cells react disproportionately negatively to a substance than other cell types, then that substance could be useful to treat cancer. All forms of hormesis are basically an extension of this idea: that the harm done by a substance can be otherwise offset by positive effects.

> If cancer cells react disproportionately negatively to a substance

The radiation is not a "substance" it's a radiation, the destructive and completely non-selective bombardment of all the molecules reached by it. It's not a chemical effect at all, but a nuclear one.

I suggest that those who claim the additional low dosages are beneficial start to expose themselves to such. Somehow I doubt they'd do it. It's always for somebody else.

There's no substance here other than being pedantic and silly in equal measure.

Somebody denying knowing the difference between physical and chemical processes and then repeating it as the argument is really rare for me to see.

I was using the chemical process of chemotherapy as an example of a disproportionate effect of a process. The specific process chosen by me was immaterial to the argument, except that it was a convenient example of the effect I wished to describe. My use of the word substance was perhaps imprecise, as it is usually reserved for items with mass, which ionizing radiation does not have. But it was, again, immaterial to the idea of a disproportionate effect, which is what I was actually conveying. And I am choosing to label as pedantic the attempt to disarm my point by discussing the word chosen as opposed to the point being made.

Damaged DNA gets repaired. The proposed mechanism for hormesis is that low levels of radiation stimulate the repair process and get the immune system to step in earlier. I have no idea if this is really true, but it doesn't seem absurd on its face.

There's no observed instance of such "earlier repair," it's just an invented "hypothesis." Only the non-linearity is observed, and not even by majority of the experiments. The explanation for the observed non-linearity is that the single impacted cells simply have time to die (or be targeted by the white cells) at low levels, whereas at higher dosages there are enough cells for cancer to progress more often. It's just the game of probabilities at the levels at which we have enough noise (low enough doses).