Udayana, also known as Udayanācārya, was a very important Hindu logician of the tenth century who attempted to reconcile the views held by the two major schools of logic. This became the root of the Navya-Nyāya school of the thirteenth century, established by the Gangesha Upadhyaya school of "right" reasoning, which is still recognized and followed in some regions of India today. He lived in Kariyan village in Mithila, near present-day Darbhanga, Bihar state, India. Udayana wrote a sub-gloss on Vachaspati's work called the Nyaya-vaartika-taatparya-tiikaa-parishuddhi. He wrote several other works such as the Kusumanjali, Atma-tattva-viveka, Kiranaavali and Nyaya-parishishhta. He is given credit by Naiyâyikas for having demolished in a final fashion the claims of the Buddhist logicians. All his known works are thought to have been preserved, attesting to the importance given to him in Indian philosophy.
Udayana's Nyayakusumanjali gave the following nine arguments to prove the existence of a creative God.
Kāryāt : The world is an effect, all effects have efficient cause, hence the world must have an efficient cause. That efficient cause is God.
Āyojanāt : Atoms are inactive. To form a substance, they must combine. To combine, they must move. Nothing moves without intelligence and a source of motion. Since we perceive substance, some intelligent source must have moved the inactive atoms. That intelligent source is God.
Dhŗtyādéḥ : Something sustains this world. Something destroys this world. Unintelligent Adrsta cannot do this. We must infer that something intelligent is behind it. That is God.
Padāt : Each word has meaning and represents an object. This representational power of words has a cause. That cause is God.
Pratyayataḥ : Vedas are infallible. Human beings are fallible. Infallible Vedas cannot have been authored by fallible human beings. Someone authored the infallible Vedas. That author is God.
Shrutéḥ : The infallible Vedas testify to the existence of God. Thus God exists.
Vākyāt : Vedas deal with moral laws, the rights and the wrongs. These are divine. Divine injunctions and prohibitions can only come from a divine creator of laws. That divine creator is God.
Samkhyāviśeşāt : By rules of perception, only the number "one" can ever be directly perceived. All numbers other than one are inferences and concepts created by consciousness. When man is born, his mind is incapable of inferences and concepts. He develops consciousness as he develops. The consciousness development is self-evident and proven because of man's ability with perfect numerical conception. This ability to conceive numerically perfect concepts must depend on something. That something is divine consciousness. So God must exist.
Adŗşţāt : Everybody reaps the fruits of his own actions. Merits and demerits accrue from his own actions. An unseen power keeps a balance sheet of the merit and demerit. But since this unseen power is unintelligent, it needs intelligent guidance to work. That intelligent guide is God.
Other works by Udayana
Seven works have been ascribed to Udayana. The following are the titles of the works in the chronological order in which they are believed to have been composed.
Laksanamala: This is a short manual giving very clear definitions and the main divisions of the sixteen categories of the Nyaya and the six categories of the Vaisesika system.
Laksanavali : This work resembles the Laksanamala in form, purpose and method of treatment. It differs from the latter in that it deals exclusively with the Vaisesika categories and their subdivisions.
Atmatattvaviveka: This is an independent work in four chapters of varying lengths. Each of these chapters is devoted to refute different theories put forward to establish the non-existence of a permanent soul such as conceived by the Nyäya-Vaisesikas.
Nyayakusumafijali:
Nyayaparisista: This deals exclusively with the Jatis and Nigrahasthanas, which form the subject matter of the fifth chapter of the Nyayasutras.
Nyayavarttikatatparyaparisuddhi: This is an elaborate commentary on the Nyäyavarttikatätparyatika of Vacaspatimisra.
Kiranavali: This is a commentary on the Padarthadharmasamgraha of Prasastapada.
