The number of different synthetic chemical compounds that are known to be carcinogenic but are nonetheless used as pe...

SamA on January 20, 2020

Hello @aahn,

Let's break down this argument.

Conclusion: It is absurd to suppose that the rise in the cancer rate in recent decades is due to synthetic carcinogens.
Why?
Support: Because there are far fewer synthetic carcinogens in use than there are nonsynthetic carcinogenic compounds.

I try to identify the flaw before I look at the answer choices. Is the number of carcinogens relevant? What if the few synthetic carcinogens are much more powerful? What if they are present in much higher concentrations? Despite the lower number, they could still be responsible for the rise in the cancer rate. The argument is weak.

Remember that we are talking about the cancer rate. So even if these synthetic compounds have other toxins, they wouldn't be the cause of the cancer rate spike. If something causes cancer, it becomes a carcinogen by definition. These toxins may cause health issues, but not the one that we are looking for. This is why C is incorrect.

D is better, because it brings another factor into play. The relatively low number of synthetic carcinogens doesn't matter, because people are exposed to these chemicals more frequently. This suggests that it is not absurd to suppose that synthetic compounds are the cause of the cancer rate increase.