does not follow either that it is not luminous, or that its luminousness
depends on something else; the fact rather is that the lamp being of
luminous nature shines itself and illumines with its light other things
also. To explain.--The one substance tejas, i.e. fire or heat, subsists
in a double form, viz. as light (prabha), and as luminous matter.
Although light is a quality of luminous substantial things, it is in
itself nothing but the substance tejas, not a mere quality like e.g.
whiteness; for it exists also apart from its substrates, and possesses
colour (which is a quality). Having thus attributes different from those
of qualities such as whiteness and so on, and possessing illumining
power, it is the substance tejas, not anything else (e.g. a quality).
Illumining power belongs to it, because it lights up itself and other
things. At the same time it is practically treated as a quality because
it always has the substance tejas for its substrate, and depends on it.
This must not be objected to on the ground that what is called light is
really nothing but dissolving particles of matter which proceed from the
substance tejas; for if this were so, shining gems and the sun would in
the end consume themselves completely. Moreover, if the flame of a lamp
consisted of dissolving particles of matter, it would never be
apprehended as a whole; for no reason can be stated why those particles
should regularly rise in an agglomerated form to the height of four
fingers breadth, and after that simultaneously disperse themselves
uniformly in all directions--upwards, sideways, and downwards. The fact
is that the flame of the lamp together with its light is produced anew
every moment and again vanishes every moment; as we may infer from the
successive combination of sufficient causes (viz. particles of oil and
wick) and from its coming to an end when those causes are completely
consumed.

Analogously to the lamp, the Self is essentially intelligent (kid-rupa),