Recently we discussed reductio ad absurdum, which is disproof of a proposition by showing an absurdity to which it leads. Here is another good example of reductio ad absurdum:
Author Theodore Dalrymple noticed some large posters that declared “Science needs women.” He commented:
“Science does not need women any more than it needs foot fetishists, pole-vaulters, or Somalis. What science needs (if an abstraction such as science can be said to need anything) is scientists. If they happen also to be foot fetishists, pole-vaulters, or Somalis, so be it: but no one in his right mind would go to any lengths to recruit for his laboratory foot fetishists, pole-vaulters, or Somalis for those characteristics alone.”Analysis
The author of the posters probably had wanted to propose “The people who hire scientists should hire more women,” but feared that this candid wording could make his proposition sound like the subjective opinion of a social meddler. So he tarted up his proposition to sound like an axiom: “Science needs women.”
Of course, the proposition “Science needs women” is nothing more than a specific instance of the general proposition “Science needs scientists who have certain traits irrelevant to the work of scientists.” In his comment, Mr. Dalrymple disproves this general proposition by citing three laughably irrelevant traits: having a certain sexual fetish, participating in a certain sport, and being a member of a certain ethnic group.
The Takeaway: Reductio ad absurdum is a familiar way to disprove a proposition. It is effective (persuasive) and efficient (requiring few words).