Post HOC Ergo Propter HOC

Post HOC Ergo Propter HOC

We’ve reviewed Bastiat’s use of reductio ad absurdum several times now. Remember he exaggerated the arguments of his opponents to absurd extremes to make his point. Writing against protectionism, he penned his famous petition of the candlemakers against the unfair competition of the sun.  In this manner he revealed the true nature of the self-serving protectionist arguments made by his foes. Those appealing to the French government to “protect” them from their competitors were devastated by this analysis.

Bastiat’s opponents cried foul as he exaggerated their arguments to make his point. He did this to reveal or expose the cracks in their logic, or to shine light on what might otherwise be concealed. His exaggeration was meant to bring clarity. Reductio ad absurdum is a method of argument. Logical fallacies are a different animal, much as Bastiat’s opponents would have had people think otherwise.

Logical fallacies are sometimes unintentional, the result of a stated idea or opinion inadequately examined.  Sometimes, however, it is used to obfuscate intentionally. Let’s look at some. Below are examples of post hoc ergo propter hoc and logical non sequiturs, sort of a “true, true and unrelated” logical flaw.

Man uses gasoline.  We had a really hot summer.  Man’s using gasoline is responsible for our really hot summer.  Got it?  Let’s try another one.

A guy gets really drunk and drives home.  No one is killed.  As a result he concludes that drunk driving is safe.

39% is greater than 31%.  People pay income tax as a percentage of their income.  Applying a greater percentage will result in more federal tax revenue (hint:  it never has as people underreport or simply earn less).

There are a lot of uninsured people in the U.S.  They will now be forced to buy insurance or others will be forced to buy it for them.  Once they are covered by insurance they will get health care.  Oops.  Coverage doesn’t mean care.  True, true and unrelated.

These logical flaws are part of the arsenal of those who masquerade as “protectors of the people.”  Watch for these flaws.  They’re everywhere.

G. Keith Smith, M.D.