Comment by A_D_E_P_T

Exactly. There are definitely people who lead higher risk lives by having exposure to carcinogens, but even that has some randomness to it. I had a family friend that smoked like a chimney his entire life, and died in his late '80s with tar-filled but cancer-free lungs. Another was an x-ray tech in the earlier days before they took nearly as many precautions as they do now to protect the technicians. No cancer.

Contrast this with some aunts and uncles who lived relatively clean lives, and still ended up dying of different cancers. Sure, I don't doubt there is a cause if we dig deep into it, but there's still some randomness.

I hear what you are saying, however, the vast majority of toxins that enter our bodies come through our mouths and out of choice. Some of these toxins, such as alcohol, cigarettes or processed meats are known to be carcinogens.

There is a very different level of dosage involved, that one cosmic ray from outer space that one time is vastly outnumbered by the trillions upon trillions of atoms that could be carcinogenic that come through the mouth, typically on a daily basis, for decades.

The body is pretty good at taking out the trash, including the mutant cells that did not reproduce properly. This goes on all the time. One cosmic ray from outer space might scramble some DNA but your body can deal with that as an isolated incident, the mutated cell(s) just get taken out with the trash.

If you overwhelm this system with too much garbage for the body to deal with then that is a causative factor that was not controlled.

It is helpful to see things this way because it enables a sense of perspective. It is not going to be 'forever chemicals', 'insecticides' or anything like that, you need to worry about. What goes in the mouth rather is what counts rather than these theoretical other things.

This means taking seriously what research in cancer, diabetes and other disease has to say. For cancer there is clear advice on what to avoid, same with diabetes and much else nobody would wish on anyone. It is defeatist to be in denial about this to assume that random cosmic rays play as much a part as the garbage we willingly consume when it comes down to it.

Eh, it's still a numbers game. Changing your chances of contracting terminal cancer in the next 5 years from 1% to 0.5% is still significant.

In this case, the specific percentages are all the significance. When a lot of the factors are controllable and a lot of them are uncontrollable, the most reasonable question is "How much do the controllable factors actually change the odds?"