Welcome
Welcome to a website devoted to illustrative examples of medical, industrial, and scientific advance that can be attributed to some prescient abductive reasoning of the type characterized in the late 1800s by America’s preeminent philosopher, Charles Sanders Peirce (1839 – 1914). For those who might wish a brief overview of what abductive reasoning is all about, a short review is given below.
At the present time, there are three sources available on this web site in the form of manuscripts that contain a variety of abductive reasoning examples.
Abductive Reasoning in the Historical Development of Communal Water Fluoridation
This manuscript is currently scheduled for print publication in Essays on the History of Dentistry.
Exemplary Tales of (Mostly) Nineteenth Century Medical and Epidemiological Discovery Through Abductive Reasoning
This source includes the seminal medically-oriented contributions from fifteen Nineteenth Century researchers: Edward Jenner; Ignaz Semmelweis; John Snow; William Budd; Louis Pasteur; Robert Koch; Joseph Lister; Patrick Manson (Ronald Ross); Paul-Louis Simond (Alexandre Yersin); Carlos Finlay (Walter Reed) Theobald Smith; Charles Nicolle.
Additional Tales of Discovery Through Abductive Reasoning
This manuscript incorporates a variety of medical, scientific, and industrial advances ranging from antiquity to the present time. It will be augmented periodically by new material.
As typically framed, Peirce’s form of abductive inference or reasoning can be phrased as follows:
The surprising fact, B, is observed But if A were true, then B would be a matter of course
Therefore, there is reason to suspect that A is true
As an example, suppose we observe that the lawn is wet when going out for the paper in the morning. If it had rained last night, it would be unsurprising that the lawn is wet; therefore, by abductive reasoning, the possibility that it rained last night is reasonable or plausible. Obviously, abducing rain last night from the evidence of a wet lawn could lead to a false conclusion – even in the absence of rain, some other process such as dew or automatic lawn sprinklers may have resulted in the lawn being wet.
Abduction is a form of logical inference that goes from an observation to a hypothesis that accounts for the observation and which explains the relevant evidence. Peirce first introduced the term “abduction” as “guessing” and said that to abduce a hypothetical explanation, say A: “it rained last night,” from an observed circumstance, say B: “the lawn is wet,” is to surmise that A may be true because then B would be a matter of course. Thus, to abduce A from B involves determining that A is sufficient (or nearly sufficient) for B to be true, but not necessary for B to be true.
The subsequent verification stages that may follow the identication of an abductive conjecture can be phrased in syllogistic terms. Assuming A represents the explanatory conjecture for our original “surprising” observation, let B’ now indicate some further observation(s) or experimental outcome(s) that should be obtained if A were true. If B’ does occur, then the conjecture A becomes even more plausible (and “stays in the running,” so to speak). If, however, B’ does not occur, the conjecture A does not then appear to be true. This situation possibly leads to the formation of an alternative explanatory hypothesis and/or to a rethinking that A being true should have led to B’ being true.
Visitors to this site who may wish to contribute other nontrivial abductive reasoning examples or comment on what is currently presented should contact the maintainer of the site:
Lawrence Hubert