Re: The drag force -- a correction squared

[Ludwik Kowalski <KowalskiL@MAIL.MONTCLAIR.EDU>]

brian whatcott wrote:

> ... I can show it is ABSOLUTELY TRUE that the population
> of Sri Lanka is strongly correlated with the change in US Stock
> market values over the last six or seven years. It is not only
> perfectly correct, and quite clear as I stated it, but totally
> misguided in terms of causality, in fact!

Two comments:

1) Cause and effect is a big and profound issue.
   Are we trying to avoid it in physics?

2) The ABSOLUTELY TRUE above is meaningless unless
   the "strongly correlated" is declared. It may be
   true if "strongly" means r>0.8. But it is not
   likely to be true if "strongly" means r>0.99.

Unlike in psychology, r>0.99 are quite common in physics. For
example, when we plot measured values of terminal speeds versus
masses of falling objects. Or when we plot amps versus volts (for
a wire at room temperature), etc.
Ludwik Kowalski