From: Ross A. Finlayson (extropy@apexinternetsoftware.com)
Date: Tue Nov 19 2002 - 22:44:53 MST
On Tuesday, November 19, 2002, at 08:16 PM, Chris Hibbert wrote:
> Lee wrote, in a public message directed to John Clark:
>> Do you at all remember your 1996 contention that is the subject of
>> this email? You and I had a long drawn out
>> argument about that, and I ended up admitting, after about
>> twenty emails, that you were right.
>
> Hmmm. I believe that 'A causes B' *implies* 'A always comes before B',
> but not that the first "means the same as" the other. Which of these
> did you intend?
>
On the contrary, "A causes B" implies that anytime there is A, then
there is B, but it does not imply that any time there is B, that some A
preceded it. Something else could cause B.
They're actually concurrent, if discussing temporal logic, which is
about causes and events in some continuous or discrete time, those
statements are about some discrete moment ir specific chain of events in
time.
> The sound of the power coming on always precedes my monitor displaying
> pixels. I deny that they have any causative relationship.
>
Well, the power has to be on for the monitor to display pixels. One
simplistic way of explaining that without explaining it all explicitly
at the atomic level in all of space-time is that the monitor's function
of displaying pixels, C, requires power to the monitor among many other
things, A, and that power to the monitor makes the sound, B.
C -> A
The "monitor displaying pixels" implies "the monitor has power"
A-> B
When "the monitor has power" then "the monitor has made the degaussing
noise".
Transitivity ensues:
C-> A
When "the monitor displays pixels" then "the monitor has made the
degaussing noise."
> As I mentioned to you face-to-face, the book "Causality" by Judea Pearl
> presents a graphical notation (based on Bayesian networks) that seems
> to allow you to learn many things about what events might be causes of
> others once you can describe probabilistic relationships among them.
>
> Chris
>
>
The butterfly can contribute to the hurricane.
Ross
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