Are Republicans Dumber Than Dirt? You Betcha!

The Republican Modus Tollens

September 24th, 2011, by Larry A. Herzberg

Republican leaders have become fond of denying well-supported facts in the last few years, including such well-confirmed phenomena as (at least partly human-induced) climate change, the proven safety of vaccines, and of course evolutionary theory. What seems to be guiding them, at least unconsciously, is (roughly) the following form of argument, known to logicians as modus tollens-

(1) If P then Q
(2) Not-Q
(3) So Not-P

This pattern of reasoning is technically valid. That is, if the premises are true, then the conclusion must be true. So criticizing any argument of this form typically involves arguing that at least one of the premises is false.

For instance, here’s the Republican modus tollens argument against climate change:

(1) If climate change is occurring, then we should regulate CO2.
(2) We shouldn’t regulate CO2.
(3) So climate change isn’t actually occurring.

Or, similarly, in the case of the vaccine Michele Bachmann doesn’t like:

(1) If the HPV vaccine is safe, then we should encourage its use.
(2) We shouldn’t encourage its use.
(3) So the HPV vaccine is not safe.

Or, finally:

(1) If evolutionary theory is true, then the biblical story of creation should be denied.
(2) The biblical story of creation should not be denied.
(3) So evolutionary theory is not true.

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