According to the Kabala, Jacobs Ladder, which was disclosed
to Jacob in a vision, was a metaphorical representation
of the powers of alchemy operating through visible nature.
The ladder was a rainbow, or prismatic staircase, between
heaven and earth. Jacobs dream symbolizes a theory of the
hermetic creation. There were said to be only two original colors,
red and blue, representing spirit and matter. Orange is red
mixing with the yellow light of the sun; yellow is the radiance
of the sun itself; green is blue and yellow; indigo is blue tinctured
with red; and violet is produced by the mingling of red
and blue. The sun is alchemic gold, and the moon is alchemic
silver. It was believed that all earthly creations were produced
through the interaction of these two potent ruling spirits.
Jacobs Ladder is also part of the symbolism of the high
grades of Freemasonry