64 How to Win Every Argument
No fictional character ever attracted fan clubs in distant countries like
pop stars do. Sherlock Holmes does, of course, but he's simply the
exception that proves the rule.
(An elementary fallacy, dear Watson.)There is a very loose way in which an exception can help to
point to an otherwise general truth. If we all recognize an
exception as remarkable, and identify it as such, then it does
show that we accept that the rule which it counters does usually
apply. In this sense, the one case we recognize as a freak points
to the otherwise general truth:
Medical advances are made by painstaking research, not by chance. I
know there was penicillin, but everyone knows that was a chance in a
million.
(Whether true or not, this is a legitimate line of argument provided
the rule is not claimed as universal. Everyone's acknowledgement of
the unique exception points to a rule which says the opposite, with
this one exception.)Even in this specialized case, the exception disproves the uni-
versal rule. The trouble with sweeping statements is that it really
does take only one exception to negate them. The medieval
world abounded with universal which assured people that the
sun would always rise and set each day, and that there could be
no such thing as a black swan. A visit to the land of the midnight
sun scuppered the first one, and the discovery of black swans in
Australia polished off the second. It would be pleasant for many
people if they could live in a world of certainties, surrounded by
huge general truths. Exceptions come baying at that cosy world
like wolves at the fringes of a camp-fire. They introduce uncer-
tainties and doubts, and the temptation there is to use the