[dekhn]

Why would it seem logical that smoking marijuana would cause lung cancer? That seems like an overly simplified model for cancer.

Anyway, there is no data showing smoking marijuana causes lung cancer (rather, there is no high quality data. I'm sure some NIDA-funding scientists have found otherwise, but it's not considered correct).

The NSF review concluded that, at most, smoking marijuana causes respiratory problems, but not lung cancer. The only type of cancer positively associated with marijuana smoking was a form of prostate cancer, which happens to be easily treated.

[int_19h]

Logical in a sense that it's a reasonable initial premise in the absence of other evidence. Not saying that it's true, but if you don't know if it's true or not, and you know that smoking other things does give you cancer, that's the side I'd err on.

[dekhn]

nope, the null hypothesis is "smoking something does not give you cancer". That smoking other things gives you cancer is specific to what they contain.