supervenience

CSGnet Archive CSG1994
1

And from the same B, you can get A0, A1, A2 ... ? This sounds a lot like

>solving a problem by naming it. If B is a set of readings from a
>spectrograph (say a plot of intensity versus wavelength displayed on a
>CRT screen), and A0 is the color person a0 sees, B0 is the color person
>b0 sees, and so forth, where does this supervention take place?

It's 'supervenience', not 'supervention' (a little trick to show up
people who don't have the right friends to correct them, the first time
they make that mistake). It's not a process, so it doesn't take place
anywhere. What it's for is to let you say things such as that a disk
has a particular virus on it and that virus caused the computer to
crash, without having to claim that computer viruses are fundamental
consitutuents of the universe.

It does seem a bit odd that each differently-wired PIF will detect a
different An supervening on the one B, but I can't actually see
anything wrong with it. And would you say it was a fundamental mistake to
say that the computer disk you sent me about a year and a half ago had
Litte Man 2 on it, just because LM2 is really made up of magnetic
domains?

>No, not at all. Look at Rick Marken's spread-sheet model again. The
>second level perceptions are arbitrary combinations of the first-level
>perceptions, which are arbitrary combinations of the external variables.
>Yet perceptions at both levels (actually all three levels) are perfectly
>controllable by acting in the usual manner -- by having an effect on
>lower-level reference signals, or on external variables.

Hmm, I'll have to think about this one some more, but it seems to me
that it would be rather easy to slap sensors and effectors together
in such a way that the the sensors could not achieve their reference
levels. Rick's spreadsheet world is kinda simple compared to the one we
live in.

Avery.Andrews@anu.edu.au

2

[Avery Andrews 940916.1518 Eastern Oz Time]
(Bill Powers (940914.1445 MDT))

What philosophers say is that 'purpleness' exists, but it 'supervenes
on' light-spectra. This is pretty close to saying that purpleness is a
CEV. For A to supervene on B implies, among other things, that you
can't get a change in A without a change in B, but there may be plenty
of changes in B that produce no change in A (lots of different spectra
are purple).

I think this is sensible, and in accordance with ordinary usage, as when
I say that there is no command.com file on the floppy disk I am holding:
command.com files supervene on track&sector disk structures, which
supervene on magnetic domains, which supervene on molecular structures,
and so on.

So I'd want to say that 'exists' is one concept; while 'exists as a
fundamental building-block of the physical universe' is another.

If we take CEVs/outputs of PIFs one at a time, they are arbitrary, as
has often been pointed out. But creatures organized along the lines
suggested by PCT need what I'll call 'useful suites' of PIFs, such
that the outputs of some of them can be controlled by controlling the
outputs of others. This is a strong constraint, and note that it resides
entirely in the external world.

Avery.Andrews@anu.edu.au