The nineteenth yoga sutra explains about the essential difference of the seer with the consciousness, though there exists but a thin line for a commonplace man. Consciousness can be seen, the seer cannot, consciousness is foreseeable and perceptible, the seer is not- it is self-illuminative. Consciousness shines in the borrowed light of the seer; the seer is thus absolute. The level of seer and consciousness varies and increases, according to the capability of an individual. The seer can be object and subject simultaneously, consciousness cannot.

na not
tat that
svabhasam self-illuminative
drsyatvat because of its knowability or perceptibility

Consciousness cannot illumine itself, because it is a knowable object.

Consciousness can be seen as an object. It is knowable and perceptible. It is not self-illuminative like the seer.

Consciousness being the seedling of the seer, its growth and luminosity depends upon the seed - the light of the seer. Its own light is like that of the moon, which is reflected light from the sun. The seer represents the sun, and consciousness the moon. As a child feels strong and secure in the presence of its parents, consciousness, the child of the seer, draws its strength from the seer.

Consciousness, like the senses of perception, can generally see an object but not its own form. For an average person, the eyes pose as the seer when comprehending worldly objects. For an intellectual person, the eyes become the seen, and the mind the seer. For an enlightened person, mind and intelligence become objects for the consciousness. But for the wise seer, consciousness itself becomes the object perceived.

The seer can be subject and object at the same time; consciousness cannot. It may hence be deduced that consciousness has no light of its own. When the borrowed light of consciousness is drawn back to its source, the seer, or soul, glows brilliantly. (II. 19-20.)