- Hasty generalization is the inductive extrapolation to an entire population, based on a sample that is nonrepresentative. Often the sample is too small to be representative, but smallness does not necessarily imply the fallacy of hasty generalization. A sample of only two or three can be enough if one is dealing with a uniform and representative property: for example, learning not to touch fire. Hasty generalization is frequent among non-scientists; it is the origin of many superstitions. A key difference between scientific and popular induction is that the latter usually ignores the need for a representative sample. The consequence is vulnerability to hasty generalization.
Hasty generalization is quite similar to the fallacy of false extrapolation to the whole. The two differ, however, in the scopes of their conclusions: a general statement about every member of a population (hasty generalization) or the collective behavior of a class (false extrapolation to the whole).
Hasty generalization: “Wristwatches with radium dials are safe, so all radium samples are safe.”
False extrapolation to the whole: “The half-life of a radium-226 atom is 1622 years; thus brief exposure to radium poses negligible hazard.”
Which is this? “I seldom detect the effect, so the effect must be rare.”
H. H. Bauer, a chemist and self-proclaimed expert in STS (science, technology, and society), succeeded in packing a remarkable number of the foregoing fallacy types into a single paragraph:
“In what sense, then, are the social sciences actually science? They have no unifying paradigm or the intellectual consensus that goes with it. They have not produced distinctive and reliable knowledge that is respected or valued by human society as a whole. Yet those are the very qualities for which the natural sciences are noted and respected; they are the qualities that we associate with something being scientific - that is, authoritatively trustworthy. The social sciences are simply not, in the accepted meaning of the term, scientific. And that conclusion has been reached by at least a few practicing social scientists -- for example, Ernest Gellner.” [Bauer, 1994]
Bauer’s argument succumbs to at least seven fallacies:
- Suppressed evidence: His assertion that none of the social sciences has a paradigm is incorrect.
- Suppressed evidence: To claim that the social sciences have not produced reliable knowledge, one must ignore countless concepts such as supply and demand (economics), stimulus and response (psychology), human impacts of environmental change (geography), and human impacts of racial and gender stereotypes (sociology).
- False dichotomy: He assumes that the accumulated knowledge of all of the social sciences can be classified as either having or not having a consensus. In actuality, consensus is a continuum and degree of consensus varies tremendously both within and among fields.
- Mob appeal: He claims that ‘human society as a whole’ determines the reliability of knowledge.
- Straw-man: His definition of ‘scientific’ as ‘authoritatively trustworthy’ is not merely a weak assumption; it is a deliberate misrepresentation.
- Appeal to authority: He seeks validation for his stance by quoting one social scientist.
- False extrapolation to the whole: He applies a conclusion based mainly on sociology to all social sciences.
