Just the Facts, Ma’am: Reasoning is Not Dead, Jim

As a kid, I watched Dragnet on an aging, black-and-white TV, back in the day when changing the channel required getting up and actually rotating the TV's channel selector. I still recall the dum, de, DUM, DUM Dragnet theme and Jack Webb's monotonic voiceover advising us that the stories we were about to see were true, a meme continued from its radio antecedents. In one ironic twist, the intrepid Joe Friday's catchphrase "Just the facts, ma'am" soon entered the popular lexicon, even though Joe never uttered exactly that phrase, merely several related variants.

In contrast, Star Trek's iconic, "He's dead, Jim" phrase, was actually uttered by Dr. McCoy. Woe be unto any "red shirt" extras who joined the away team, only to die, just before the first commercial break, as Bones looked up at Jim and began to speak those fateful words. So publicly imprinted was the phrase that DeForest Kelley later expressed some concern that "He's dead, Jim" might be the epitaph on his own tombstone. It was not, but at least one obituary opened with the phrase.

When innocuous, these cultural memes are an intellectual and social shorthand, framing a larger social context, quickly and concisely. "Just the facts, ma'am" became a caricature of deadpan delivery and dispassionate situational analysis, whereas "He's dead, Jim" poked fun at Star Trek's often formulaic storylines. In an extended riff, John Scalzi later wrote an entire novel, entitled Red Shirts, on the dangers of self-aware characters trapped and under the influence of badly written television script.

The more sinister variants of cultural catchphrases can label and ostracize, reinforcing inaccurate stereotypes and disenfranchising entire social, ethnic, or cultural groups. Simply put, such memes can become an intellectual crutch, a way to avoid rational and thoughtful discourse and ignore the timeless importance of fact-based reasoning. A line often attributed to the late Senator Daniel Patrick Moynihan captures the essence of such fact-based discourse, "Everyone is entitled to their own opinions, but they are not entitled to their own facts."

Of course, purported facts are not themselves facts; establishing actual facts (a neologism, for sure) is the essential prerequisite for fact-based reasoning. If one source claims it is raining and another says it is not, the wise person does not report both as opinions. Rather, he or she looks outside and ascertains the existence, as well as the time, type, location, and geographic dispersion of the purported precipitation. As Lincoln once said, "Calling a tail a leg does not make it so."

Nor does saying something loudly and repeatedly make it a fact, even if the source is both respected and authoritative. Indeed, appealing to authority is one of the biggest risks and fallacies in common, public discourse. It ranks right up there with strawman arguments and false dichotomies among the informal fallacies. (I will return to these informal fallacies as well as some of the formal ones discussed in elementary propositional logic, as found in introductory philosophy classes.)

An appeal to authority is especially pernicious in scientific disciplines. Richard Feynman reinforced the magnitude and the danger of this risk in describing the scientific method, "It doesn't make any difference how beautiful your guess is, it doesn't matter how smart you are, who made the guess, or what his name is… If it disagrees with experiment, it's wrong. That's all there is to it." (See The Epistemology of Science for a few musings on the interplay of scientific discourse and a lay audience.)

In a world of social memes, tweetstorms, fake news (real and otherwise), and alternative facts, it is especially important to think, analyze, and verify, and do so with careful deliberation. (See Contemplative Reflection and Instantaneous Communication for some thoughts on the dangers of speaking before thinking.)

What science fiction writer Bruce Sterling once called the major consensus narrative, a perhaps more erudite version of truthiness, is just that, a social construct, a shared belief. It may (or may not) be sophistry, fully grounded in the facts. (See A Conversation on Designing the Future, where Bruce and I riff on the interplay of technology and social behavior.)

In that spirit, it is worth remembering and holding dear some classic rules and frequent fallacies of logical reasoning. Many valued logics, higher order logics, measure theory, incompleteness theorems, the Chomsky hierarchy, Zermelo-Fraenkel set theory, and decidability are fascinating and worthy topics, ones I have spent many a day and night pondering, building constructive and non-constructive proofs, but they, like how Gödel struck down Hilbert's dream, are topics for another day.

Just a few basics of propositional logic and a bit of first order predicate logic, along with recognition of informal fallacies, cover most everyday needs. Here are just a few of the more common fallacies to remember and avoid:

• Ad hominem fallacy – discrediting an idea by attacking an individual or group
  • "Dan is uneducated, so climate change cannot be happening."
• Appeal to authority fallacy – adopting a position because of those who support it
  • "Your father said you could run fast; it must be true."
• Circular logic fallacy -- A is true because B is true; B is true because A is true
  • "You must save money to retire because it takes money to retire."
• Affirming a disjunct – A or B; A, therefore not B (both can be true simultaneously)
  • "The sun is up or it is springtime."
• Affirming the consequent – P implies Q; Q, therefore P (Q can be true even if P is not)
  • "Dan is tall implies he is a basketball player. He is a basketball player. Therefore, he is tall." (There are short basketball players)
• Denying the antecedent – P implies Q; therefore, if not P then not Q (again, Q can still be true)
  • "Dan is tall implies he is a basketball player. If Dan is not tall, then he is not a basketball player." (Again, there are short basketball players.)

These fallacies are everywhere if one reads the news critically or listens carefully to many public statements, and one must be diligent and vigilant to avoid being lured unaware by these seductive Sirens. Remember, given an inconsistent set of axioms (i.e. contradictory "facts"), any statement can be "proven" to be true or false.

Other fallacies abound in first order logic via misuse of existential and universal quantifiers (e.g., the existence of an instance does not imply universality); hasty generalizations are one instance of such. Likewise, here are two simple logic rules that everyone should remember; they are valued, everyday friends:

• Modus tollens – P implies Q; not Q, therefore not P"
  • "It is raining implies the ground is wet. The ground is not wet, therefore it is not raining."
• Modus ponens – P implies Q; P, therefore Q
  • "The sun has set implies it is dark. The sun has set, therefore it is dark."

Notice how similar modus tollens and modus ponens look to affirming the consequent and denying the antecedent; it is crucial to understand the difference.

Remember, it all begins with "Just the facts," rigorously tested and verified. This solid detective work would make old Joe Friday proud. From there, logical reasoning – establishing cause and effect – will lead to other testable hypotheses. It's about following the clues.

Make no mistake, logical reasoning is definitely not dead, Jim, though it seems to have been punched in the gut and beaten bloody by a gang of angry naysayers. Fortunately, it is a bit hardier than Star Trek's red shirts. As long as we pursue just the facts logic will both live and flourish.