'One problem is in the assumption that because one is feeling better, the treatment therefore worked. This is the post

hoc, ergo propter hoc [after this, therefore because of this] logical fallacy.' 




I can’t resist a chance to knock

  This imbecilic fantasy.

Empiricism is the rock

  That underpins society;

Unbiased rationality

  Beats sugar pill-based poppycock, 

But some prefer the fallacy

  Of post hoc, ergo propter hoc.

They snipe at science round the clock;

  ‘Big Pharma’s a conspiracy!’,

But you don’t have to be John Locke

  To poke holes in their theory

That water has a memory.

  It doesn’t take a Mr Spock

To spot illogicality

  In post hoc, ergo propter hoc.


Why do these clueless ninnies flock

  To blast the inefficacy

Of what the chemist has in stock?

  It’s total bloody lunacy.

But I suppose they must be free

  To do it if I’m free to mock

Placebos and to disagree

  With post hoc, ergo propter hoc.



Prince Charles, you lend authority

  To this extraordinary crock,

But I say give the third degree

  To post hoc ergo propter hoc.

Ballade of Homeopathy