inferring from the claim that two phenomena have fluctuated together that one of those phenomena must be the sole cause of the other inferring from records concerning a past correlation between two phenomena that that correlation still exists inferring from records concerning two phenomena the existence of a common cause of the phenomena and then presenting a hypothesis about that common cause inferring from a claimed correlation between two phenomena that two other phenomena are causally connected to one another
Records from 1850 to 1900 show that in a certain region, babies' birth weights each year varied with the success of the previous year' s crops: the more successful the crops, the higher the birth weights. This indicates that the health of a newborn depends to a large extent on the amount of food available to the mother during her pregnancy.
The argument proceeds by