Re: [Phys-L] causality -- correction

[John Denker <jsd@av8n.com>]

On 2/7/19 9:29 PM, I wrote:

> A few years ago I went on a rampage and revised
> a great many of my web pages to eradicate words that could
> be interpreted in terms of causation when that wasn't what
> was intended.
>
> I thought the eradication would be difficult, but it really
> wasn't.  There are plenty of ways of saying what we mean
> without saying things we don't mean.

That's not entirely true, and I regret saying it.

It's perhaps "mostly" true, but there are some huge nasty
exceptions, starting with the word /force/ itself.

As I like to say:
	You cannot force people to believe there
	is only one definition of the word /force/.
The physics definition is not the only definition.

This is a tremendously big deal, especially when it comes
to misconceptions about force versus causation, because the
longstanding nontechnical meaning of /force/ does imply
causation:
    "The robber forced the lady to give him her purse."

The Latin root /fortis/ is not the word the Romans used for
physics-force, but the word they did use has all the same
problems: pello,pellere means to push, but it also means
to cause.  Hence English words like compel.

Pedagogically speaking, you cannot erase the nontechnical
definition and you shouldn't try.  The best you can do is
to ask students to set up a mental "traffic cop" to direct
force-related thoughts in the physics direction /when appropriate/
and in the nontechnical direction /when appropriate/.

  I have major reservations about parts of the FCI:  The most
  troublesome questions on the FCI don't seem like physics
  questions to me;  mostly they seem like smart-aleck word
  games, requiring students to use the physics definition
  in situations where the nontechnical definition would make
  at least as much sense.

  It could be argued that students should realize that they
  are sitting in a physics classroom and therefore they should
  use the physics definition exclusively, but I don't buy that
  argument.  Everybody -- physicists included -- uses the
  nontechnical definition routinely, in class and otherwise.
  And students are not accustomed to getting smart-aleck trick
  questions in physics class.  Most end-of-chapter questions
  are not like that.

  The obvious take-home message and action item is simple:
  If you want to get a large FCI gain, no amount of harping
  on the physics definition /by itself/ will do the job.
  You have to:
  -- Acknowledge that there are two definitions.
  -- Teach students to choose the definition that is appropriate
   to a given context.
  -- Then teach them to be street-wise about smart-aleck
   questions that tempt them to use one definition and then
   grade them according to the other definition.  (This isn't
   physics, but it's a useful skill nevertheless.)

===========

Tangential remark:  Most people think that scientific terminology
is super-precise, but it really isn't.  There are lots of words
that either
 -- have a technical meaning that conflicts with the nontechnical
  meaning, or
 -- have multiple conflicting technical meanings.

But that's a topic for another day.