Udayana

Udayana, also known as Udayanācārya (Udyanacharya, or Master Udayana), was a very important Hindu logician of the tenth century who attempted to reconcile the views held by the two major schools of logic (Nyaya and Vaisheshika). This became the root of the Navya-Nyāya school of the thirteenth century, established by the Gangesha Upadhyaya ("New Nyāya") school of "right" reasoning, which is still recognized and followed in some regions of India. 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 (also called Bodha siddhi or Bodha shuddhi).

He is given credit by Naiyâyikas for having demolished in a final fashion the claims of the Buddhist logicians. All his works, or at least all of which we know, have been preserved, which attest to the respect in which he was held from the beginning.

Two schools of thought for logical proof of the existence of God exist in Hindu philosophy. The old Nyaya system was concerned with the critical examination of the objects of knowledge by means of logical proof, while the earlier Vaiseshika system dealt with particulars—objects that can be thought of and named. Udayana assumed, with the Vaiseshika, that the world was formed by atoms, from which physical bodies also derived. But he was equally concerned with the mind and its right apprehension of objects in nature. His vigorous thinking was set forth in the Nyāya-Kusumānjali and the Bauddhadhikkāra, the latter an attack on the atheistic thesis of Buddhism. Living in a period of lively controversy with the Buddhists, Udayana defended his belief in a personal God by resorting to the two natures of the world: cause and effect. The presence of the world is an effect that cannot be explained by the activity of atoms alone. A supreme being had to cause the effect and regulate the activity of the atoms; hence, according to Udayana, God exists.

In a debate with Buddhists in India he was the final victor. After him no Buddhist philosopher undertook again a debate with Nyāya. Thus the nine-centuries long debate ended.

Udayana's Nyayakusumanjali gave the following nine arguments to prove the existence of creative God:

• Kāryāt (lit. "from effect"): The world is an effect, all effects have efficient cause, hence the world must have an efficient cause. That efficient cause is God.
• Āyojanāt (lit., from combination): Atoms are inactive. To form a substance, they must combine. To combine, they must move. Nothing moves without intelligence and source of motion. Since we perceive substance, some intelligent source must have moved the inactive atoms. That intelligent source is God.
• Dhŗtyādéḥ (lit., from support): Something sustains this world. Something destroys this world. Unintelligent Adrsta (unseen principles of nature) cannot do this. We must infer that something intelligent is behind it. That is God.
• Padāt (lit., from word): Each word has meaning and represents an object. This representational power of words has a cause. That cause is God.
• Pratyayataḥ (lit, from faith): 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 (lit., from scriptures): The infallible Vedas testify to the existence of God. Thus God exists.
• Vākyāt (lit., from precepts): 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 (lit., from the specialty of numbers): 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 (lit., from the unforeseen): 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.