The absolute Citi (Consciousness) out of its own free will is the cause of the siddhi of the universe. Universe in this context means everything from Sadasiva down to the earth.
Siddhi means bringing into manifestation, maintenance, and withdrawal. Also may mean bhoga (experience) and moksa (liberation). Of these also the absolute freedom of the ultimate divine consciousness is the cause.
Citi – The absolute consciousness alone is the power that brings about manifestation. Maya, Prakrti is not the cause of manifestation. Inasmuch as it (Citi) is the source of both subject, object, and pramana (means of proof), no means of proof can prove it (i.e. it is its own source).
The word ‘hetu’ in the sutra means not only cause in which sense it has been already interpreted above. It also means ‘means’. So Citi is also the means of the individual’s ascension to the highest consciousness where he becomes identified with the divine consciousness.
Citi has been used in the singular to show that it is unlimited by space, time etc. It has been called svatantra (of free will) in order to show that it by itself is powerful to bring about the universe without the aid of Maya etc. Citi is, therefore, the cause of manifestation, the means of rising to Siva, and also the highest end.