Some beings express their consciousness in an autonomous or unconscious manner. Autonomic functioning is their nature. It seems that they are not conscious at all. What we call matter falls in that category. Behaviour of matter is totally deterministic whereas consciousness expression of consciousness is accompanied by a measure of freedom.
sanskrit expression of this attribute used the word tamas which means mental darkness, ignorance and gloom. Activity is limited to the autonomous or unconscious, totally under the control of nature; there is no activity which may be described as self driven.
While this attribute is the characteristic of the inanimate, when applied to an animate it describes heir state of inactivity like that of the inanimate with no life force.
The word tamas denotes materiality and is described as the result of spiritual ignorance. It results from ignorance and deludes all embodied beings. It attaches them to inactivity, dullness, laziness, sloth and sleep. Nothing seems to motivate a person when the mind identifies primarily with this attribute.
This is a quote from the Bhagvad Gita:
“Darkness, dullness, stagnation,
Indolence, confusion, torpor,
inertia: these appear
when tamas is the ruling trait.”