Hand Waving

In an argument, "hand waving" is drawing or assuming conclusions without evidence. Outside of an argument, it typically refers to skipping over a complex explanation or assuming it is obvious. E.g., "Sam did a lot of HandWaving when asked how the rendering engine would work."

Hand waving is, among other things, a metaphor for avoiding communication.

Also known as magic hand waving or the Jedi mind trick.

Hand waving doesn't have anything to do with solving HardCodingProblems? or VooDoo. It's the practice, when confronted by a hard problem, to explain it away as an artifact of an incorrect point of view or an emotional reaction.

Used when: We hope that by hand waving the problem will magically go away.

It is often used to avoid an explanation when a problem hasn't been fixed but the symptoms have gone. Instead of acknowledging the difficult issue and working with another to analyze it and find a solution, it is simply made to magically disappear by invoking some explanation which seems to cover the facts but in fact simply hides them through various techniques.

Some hand waving tricks are: etc.

Hand waving was always the way my physics professors would discuss 'cutting out' some fairly complicated, not-really-relevant-to-the-discussion mathematics during lectures. "If we wave our hands over the chalkboard, we get the following..." -- ChadThompson

traditionally, this is how some physics professors deal with fairly complicated, extremely-relevant-to-the-discussion mathematics as well ;)

[I actually had a calculus instructor who would use this technique for cutting out long winded and boring proofs. Sadly, he sometimes also cut out vital and impenetrable proofs, leaving his students in the dark. A buddy of mine joked that when he was solving heavy math on the job and he'd get to one of these kinds of problems he would tell his boss that he'd been trained to wave his hands.]

See: JD Jackson, Classical Electrodynamics for the seminal work on hand waving. ;-)

A maths professor at University of Helsinki used to warn people that the following would be a load of inexact hand waving when he started (finally) to talk about things like graphical representations and real-world-ish applications for the theory being taught.

He could have meant it literally being that it's about graphics which he was attempting to "draw" in the air.

During a meeting about some new interface, a colleague of mine described his new idea as The Handwave of the Future

In the mathematical world hand waving has a bad reputation, similar to "proof by intimidation", where you simply announce that a step in a proof is obvious, with the implication that you can't really prove it. Sometimes you are even right about that. :-) Proof by intimidation involves raising one's voice and works best in a classroom situation. -- RobertField

Gee, that almost sounds like PointlessEvangelism. -- JasonNocks

I don't think I've ever heard "hand waving" described in a positive sense as at the top of this page. It always refers to magic hand waving. Drawing useful pictures or providing a real explanation is not hand waving. The term comes from magicians' practice of doing things that distract the audience from what is really happening. -- KrisJohnson (with minor edits, sorry)

As a former stage magician, I always took magic hand waving to refer to Prestidigitation, or SleightOfHand. We would sometimes even call it hand mucking. Distracting the audience is MisDirection?, and is best done using attractive assistants :) Cheers, -- JasonNocks

Use PerlLanguage? Need results, fast, but tired of all that tedious programming stuff? Use Acme::Handwave!


See: VoodooChickenCoding, CargoCult, XpAsCargoCult

NovemberZeroNine CategoryJargon

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