The Shapes of Things
15
redness we experience is the sensation triggered by light whose wavelength is
about 700 nm.
If the wavelength is shortened to 600 nm, our experience changes and we
see yellow instead. There is no logical connection between perceived color
and the wavelength of light: It is an arbitrary association invented by nature.
Moreover, the wavelength of lightwaves varies continuously along a spectrum,
and is not cut up into zones corresponding to different colors. The division of
the spectrum into discrete colors is a psychological phenomenon, not a physical
one. Evolution designed eyes so a distinct subjective experience accompanies
different segments of the spectrum.
What is far more difficult to accept, but equally true, is that shape also is
psychological. The reason this is hard to accept is that unlike color solid objects
occupy a definite portion of space, and their shape is that of the space they
occupy. Every chunk of solid matter has boundaries, and in that sense has
a shape. But just as an object’s color is the way we experience lightwaves of
certain frequencies, so its shape represents the specific way the visual system
reacts to it and gives it a character that we feel. The shape of an object is the
sensation we experience toward its global configuration in space.
Shape is a Gestalt quality apprehended by minds and having, for minds, a
definite experiential character. Gestalts are recognized by minds, not eyes: It is
only a mind that is able to apprehend an undivided Gestalt as a single whole.
For the physical world any one shape is as good as any other. If we see an
object as a cube, we may measure its sides and angles and find they are exactly
as we expect them to be: In the external, physical world, an object is given by
measurement and description, but for us there is more: There is the distinctive
appearance of a shape as a whole, and the experience we have when beholding
it.
Try to picture a row of triangles touching one another at the ends of their
bases. Together they have a serrated appearance, reminiscent of a saw blade,
and that’s the first impression you get. Or imagine looking at a weeping willow:
What you experience is far more than the geometry of its branches and leaves:
The image of the tree as a whole gives rise to a unique visual experience which
is difficult to put into words.
This is reminiscent of the philosophical riddle that asks, “If a tree falls in a
forest and no one hears it, does it make a sound?” Certainly it produces sound
waves in the air, but these sound waves do not actually sound like anything, for to
sound like something is a subjective experience. There is a categorical difference
between vibrations of the air and the specific experience of a sound heard by
a listener, for example the middle-C note played on a flute. Likewise a cubical
stone is an objective cube, and its shape can be verified by measurements.
15
redness we experience is the sensation triggered by light whose wavelength is
about 700 nm.
If the wavelength is shortened to 600 nm, our experience changes and we
see yellow instead. There is no logical connection between perceived color
and the wavelength of light: It is an arbitrary association invented by nature.
Moreover, the wavelength of lightwaves varies continuously along a spectrum,
and is not cut up into zones corresponding to different colors. The division of
the spectrum into discrete colors is a psychological phenomenon, not a physical
one. Evolution designed eyes so a distinct subjective experience accompanies
different segments of the spectrum.
What is far more difficult to accept, but equally true, is that shape also is
psychological. The reason this is hard to accept is that unlike color solid objects
occupy a definite portion of space, and their shape is that of the space they
occupy. Every chunk of solid matter has boundaries, and in that sense has
a shape. But just as an object’s color is the way we experience lightwaves of
certain frequencies, so its shape represents the specific way the visual system
reacts to it and gives it a character that we feel. The shape of an object is the
sensation we experience toward its global configuration in space.
Shape is a Gestalt quality apprehended by minds and having, for minds, a
definite experiential character. Gestalts are recognized by minds, not eyes: It is
only a mind that is able to apprehend an undivided Gestalt as a single whole.
For the physical world any one shape is as good as any other. If we see an
object as a cube, we may measure its sides and angles and find they are exactly
as we expect them to be: In the external, physical world, an object is given by
measurement and description, but for us there is more: There is the distinctive
appearance of a shape as a whole, and the experience we have when beholding
it.
Try to picture a row of triangles touching one another at the ends of their
bases. Together they have a serrated appearance, reminiscent of a saw blade,
and that’s the first impression you get. Or imagine looking at a weeping willow:
What you experience is far more than the geometry of its branches and leaves:
The image of the tree as a whole gives rise to a unique visual experience which
is difficult to put into words.
This is reminiscent of the philosophical riddle that asks, “If a tree falls in a
forest and no one hears it, does it make a sound?” Certainly it produces sound
waves in the air, but these sound waves do not actually sound like anything, for to
sound like something is a subjective experience. There is a categorical difference
between vibrations of the air and the specific experience of a sound heard by
a listener, for example the middle-C note played on a flute. Likewise a cubical
stone is an objective cube, and its shape can be verified by measurements.