The 'or' is meant to set aside the view previously stated. The Self
extends through the whole body by means of its quality, viz. knowledge
or consciousness. 'As light.' As the light of things abiding in one
place--such as gems, the sun, and so on--is seen to extend to many
places, so the consciousness of the Self dwelling in the heart pervades
the entire body. That the knowledge of the knowing subject may extend
beyond its substrate, as the light of a luminous body does, we have
already explained under the first Sûtra.--But it has been said that the
Self is _mere_ knowledge; how then can knowledge be said to be a quality--
which is something different from the essential nature of a thing?--This
the next Sûtra explains.
27. There is distinction as in the case of smell; and thus Scripture
declares.
Just as smell, which is perceived as a quality of earth, is distinct
from earth; thus knowledge of which we are conscious as the quality of a
knowing subject--which relation expresses itself in judgments such as 'I
know'--is different from the knowing subject. Scriptural texts also
prove this relation, as e.g. 'This Person knows.'