[lit-ideas] Re: "Colourless Objects" (Was: Wittgenstein's Universe)
- From: Robert.Paul@xxxxxxxxxxxxxxxxxx (Robert Paul)
- To: lit-ideas@xxxxxxxxxxxxx
- Date: 19 May 2004 19:21:07 PDT
JL writes:
>The presence of the '-' (in 'wave-length') suggests that 'blue' applies to
'length'? (But can a length be blue, R. Paul?). On the other hand, if it
applies to 'wave', shouldn't it be 'blue-wave length'?<
No. A 'length' cannot be blue or any other color. This is because there is no
such _thing_ as length. The belief that there is comes from thinking that there
must be a substance answering to every substantive. That this diagnosis can be
found in the Blue Book (p. 1) should come as no surprise.
One might say that colors are present in light: light passed through a
spectrometer, e.g. a simple prism, will be spread into the colors emitted by the
light source, and not all light sources emit the same light, because the light
they omit comes from the excitation of different atoms. The light from the sun
will be spread into a smooth, continuous spectrum which contains all of the
colors of the visible spectrum, with no 'gaps,' but the light from a sodium
vapor street lamp will be displayed as bright yellow, and some dimmer colors,
with bands of 'no color.'
The Geary Theory doesn't account for why certain light sources appear the colors
they appear, for it deals only with reflected light. (So far.) The light from a
red laser, e.g., is red (what would you expect?) and if the laser is powerful
enough you can actually see the beam of concentrated photons as it passes
through the atmosphere (or through a vacuum). The beam looks red, or is red, if
you like.
Why the 'red' in sunlight doesn't appear red until we see it reflected or
refracted (i.e., why we don't see the red 'as it goes by') is a question that
only David Savory can answer.
There is a really neat 'mini spectrometer' at:
http://mo-www.harvard.edu/Java/MiniSpectroscopy.html
By the way, there is no such thing as 'colour,' and hasn't been since 1727.
Robert Paul
Reed College
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