Recognizing Logical Fallacies

Ever heard of circular reasoning? Wikipedia defines it as “a formal logical fallacy in which the proposition to be proved is assumed implicitly or explicitly in one of the premises.”

I found a witty rejoinder to that put-down in the Reference Frame column in the November 2006 of Physics Today entitled “Reasonably effective: 1. Deconstructing a miracle” by Frank Wilczek, the Herman Feshback Professor of Physics at MIT. The setting is conjured up by the sentence “Mathematics is effective in describing nature because nature obeys mathematical concepts.”

In Professor Wilczek’s own rebuttal: “the world line of a circular argument can be an ascending helix.” For the less mathematically inclined, a helix is a curve in 3-dimensional space, but an ascending helix looks circular when viewed from the top, and an ascending spiral when viewed from the side. So on closer examination, the reasoning is not really circular, and hence, not a logical fallacy. Of course one still has to substantiate that with the facts of the arguments, without which it remains a hollow claim.

That brings me to another logical fallacy, ad hominem argument, which, as defined by Wikipedia, "involves replying to an argument or assertion by attacking the person presenting the argument or assertion rather than the argument itself". This is tantamount to killing the messenger for the message, which is a dishonorable act in ancient Chinese military warfare.

In lawyer parlance, this ploy is called discrediting the witness and is often employed to mangle the credibility of a key witness to shreds, at least in TV crime series.

In the political arena, a straw man argument is in vogue. According to Wikipedia, it is “a logical fallacy based on misrepresentation of an opponent's position. To "set up a straw man" or "set up a straw-man argument" is to create a position that is easy to refute, then attribute that position to the opponent.”

While most of us do not actually engage in arguments, be they in courts or out of courts such as public forums, or peer reviews, we often do debate within ourselves as to the veracity of a claim, be it of local implications such as zoning for area development or siting of hazardous facilities, or of global ramifications such as choosing fuel-efficient hybrid cars over gas guzzlers. Therefore, we must be circumspect and discerning of actions that seem innocuous but are in actual fact potentially detrimental. We must be able to see through all the glib talks, the sleek presentations, and the cloak of logical fallacies, several of which are enumerated above.

Here is an analogy I read in a Chinese blog by Venerable Hui Zheng whom I’ve blogged previously, but used here in a different sense to illustrate our tendency to see the tree for the forest.

A teacher enters a class and puts a white dot on the center of the blackboard. He then asks the class, “What is that?”

“A white dot,” the whole class answers in unison.

Feigning surprise, the teacher asks in amazement, “Is there a white dot only? Don’t you all see the big black board?”

In his effort, Venerable Master Hui Zheng uses the the reverse, i.e., a black dot in the center of a white board, to drive home the point that we often see the “black spot” on others, but missing the much greater space of “impeccably white” that others exhibit. Therefore, we should frequently pardon the weaknesses of others. At the same time, we should endeavor to discover their merits. This dual but complementary attitude will surely make for a harmonious world.

In my context here, my point is not to get drawn in by a particular argument (the white dot), however cogent it may seem, and become oblivious to the greater harm (black board) that may ensue. May we all have the courage to change the things that we can, the serenity to accept the things that we can’t change, and the wisdom to know the difference.