In Darwin's Shadow: The Life and Science of Alfred Russel Wallace ...

304 / In Darwin’s Shadow
individuals have the most say in their historical context. Here we catch a
glimpse of Wallace, the hard-working, common man who made a most uncommon
discovery: “It is only by patient thought and work, that new ideas,
if good and true, become adopted and utilized; while, if untrue or if not
adequately presented to the world, they are rejected or forgotten.” 7 Such is
the nature of science and history.
Counterfactuals and “What if?” History
Another path into the murky past that can aid us in discerning cause-andeffect
relationships in history is what is known in the trade as counterfactual
history, or in popular circles “What if?” history, as in its humorous extreme
“What if Napoleon had the atom bomb?” Well, what if he did? He no doubt
would have dropped it on Blücher before he arrived at Waterloo to rescue
Wellington. We know this is ridiculous, of course, but hyperbole does not
equal superfluity. In moderation we can play this game to great historical
insight, and the process even has a technical name: counterfactual
conditionals.
In logic, conditionals are statements in the form “if p, then q,” as in a more
realistic counterfactual for Waterloo where “if Blücher arrives in time to reinforce
Wellington’s troops then Napoleon loses,” where q depends on p (and
p is the antecedent since it comes before q). Counterfactual conditionals alter
the factual nature of p, where p' is counter to the facts, thus altering its
conditional element q into q'. Counterfactual conditionals are said to be modal
in nature; that is, changing the antecedent changes the modality of the causal
relationship between p and q from necessary (what had to be) to contingent
(what might have been). Change p to p' and instead of q you may get q', as
in “if Blücher does not arrive in time, Napoleon may win.” In other words,
the modal nature of the relationship between p and q changes from necessary
to contingent in counterfactual conditionals.
Counterfactual modal thinking is prevalent in works of history, as historians
try to understand causal relationships by considering what might have happened
in a different replay of the historical sequence. Histories of the American
Civil War, for example, are filled with counterfactual conditionals
whereby the South might have gained independence from the North at various
contingent stages of the war. The Battle of Antietam is a case study in counterfactual
history. 8 In preparing to defend his territory against invading Confederates,
General George B. McClellan caught a break when one of his
soldiers stumbled onto Robert E. Lee’s battle plans in the infamous Special
Orders 191, wrapped in cigar paper and accidentally dropped in an open field.
With Lee’s plans in hand, the impossibly refractory and interminably sluggish