Note 7 — Chapter IV · QUACKERY.

The following anecdote of an ignoramus, who set himself up as a doctor, furnishes a good illustration of this erroneous mode of reasoning. His first case was that of a butcher, who recovered. As he gave his patient beefsteak and wine quite liberally, he referred the cure to these articles, and put down in his note-book—beefsteak and wine will cure a butcher. His next case was that of a tailor, which, under the same treatment, resulted unsuccessfully. He, therefore, added to the above note—but will kill a tailor.

You laugh at the use which this man made of the ‘post hoc propter hoc’ mode of reasoning; but, after all, his inference is no farther from the truth than many of the inferences of wise dabblers in physic, promulgated in the newspapers, or even of learned doctors, gravely recorded in the annals of medicine. The only real difference is, that among the many preceding circumstances, to which results might be attributed, he chose one, and they chose some other, a little more plausible, perhaps, than his, but no nearer the truth.