Science Friction_ Where the Known Meets the Unknown - Michael Shermer [92]
In logic, conditionals are statements in the form “if p then q,” as in “if Blücher arrives 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, Napoleon may win.” In other words, in counterfactual conditionals the modal nature of the relationship between p and q changes from necessary to contingent.
Here we see why few students ever get past introductory logic. This philosophical mouthful becomes meaningful through real-world examples. In my first paper published on chaos theory I offered a counterfactual conditional whereby the South might have gained independence from the North during the Civil War at the Battle of Antietam.1 General George B. McClellan caught a break when one of his soldiers stumbled into Robert E. Lee’s battle plans in the infamous Order 191, wrapped in cigar paper and accidentally dropped in an open field. With Lee’s plans in hand, the impossibly refractory and interminably sluggish McClellan was able to fight Lee to a draw, thwarting the latter’s invasion plans. In the factual time line the conditional sequence is “if McClellan has Lee’s plans (p) then the invasion is turned back (q).” From this, additional conditional series arise where “if q then r (the war continues), s (England does not recognize the South as a sovereign nation), t (the Northern blockade continues), u (the South’s diminishing resources hinders their war effort), v (Lee is defeated at Gettysburg), w (Grant becomes the head Northern general), x (Sherman destroys everything in his path from Atlanta to Savannah), y (Lee surrenders to avoid the utter destruction of the South), and z (America remains a single nation).”
In my counterfactual conditional McClellan does not get Lee’s plans, he is dealt a major defeat, and the invasion continues until the South earns the recognition from England as a sovereign nation, bringing the British navy to bear on the Northern blockade (in order to maintain open trading channels), thereby allowing the South to replenish her rapidly depleting resources and carry on the war until the North finally gives up. Here p’ (McClellan does not get Lee’s plans) leads to q’ (Lee wins), with the modal cascading consequences of r’ through z’, and America ever after is divided into two nations, changing almost everything that has happened since. Whether I am right about this counterfactual is not relevant here (and in this “What if?” genre a sizable literature exists on the Civil War alone). More than just an example of the modal nature of counterfactuals, we see how they help us think about cause-and-effect relationships in historical sequences. We don’t just want to know how the Civil War unfolded, we want to know why. Why questions are deeper than how questions, and require an appropriately deeper level of analysis.
Implicit in nearly all historical narratives are counterfactual “What if?” scenarios. One cannot help but ask, “What if McClellan had not received Lee’s plans?” and therefore, “What if Lee had successfully invaded the North and obtained a peace treaty with the North?” (See figure 10.1.) The consequences are obvious and the counterfactually modal reasoning pervasive.
In another paper on chaos and history I demonstrated the highly contingent nature