[ExI] Meaningless Symbols

Stathis Papaioannou stathisp at gmail.com
Tue Jan 12 12:07:51 UTC 2010

2010/1/12 Lee Corbin <lcorbin at rawbw.com>:

> My favorite chapter of Gödel, Escher, Bach is "The Location
> of Meaning". Hofstadter points out, essentially, that there
> are two kinds of meaning: conventional and isomorphic (I'm
> not sure after all these years whether the terminology is
> mine or his).
> You speak here of conventional meaning---meaning which
> operates by convention. Our convention for "z-e-b-r-a"
> is the large striped African mammal, though obviously
> those letters could be assigned to something else.
> Isomorphic meaning, however, is not at all arbitrary.
> The depth and jiggles in the grooves of a vinyl playing
> record have, in some cases, an objective isomorphism
> to the first movement of Beethovan's fifth symphony.
> That's their undeniable meaning, no two ways about it.

Vinyl records are interesting, because the relationship between the
bumps in the grooves and the music they represent is not as
straightforward as you might think. For reasons of sound quality,
during the cutting of a record the high frequencies are boosted and
the low frequencies attenuated, and during playback this must be
undone by applying the exact inverse operation. This so-called RIAA
equalisation is traditionally achieved by using a network of
capacitors and resistors in the amplifier preamp stage.

The interesting thing about this is that there is no way of figuring
out what the equalisation curve is unless you are given that
information. I'm not sure if equalisation was used for the Voyager
golden record, but it would have made sense to record it with a flat
frequency response, otherwise the aliens would only be able to hear a
distorted version of what we sound like. But worse would have been
sending a CD, compressed audio such as an MP3 file, or encrypted
audio, in that order. That would have completely stumped the aliens,
no matter how smart they were. This is because digital files have
conventional meaning, not isomorphic meaning.

Stathis Papaioannou

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