Anvikshiki is the science of analyzing what has been said in knowledge texts (agama) and sense experience (pratyaksha). Anvikshiki has been so defined by Vatsyayana in his Nyaya-Bhashya (I.1.1). The term is analyzed as anuikshana or reflection. It thus means logical enquiry and is also called Nyaya. Vacaspati says that the Nyaya system of Hindu philosophy believes in the ‘reasoned analysis of experience’ (Nyaya-varttika-tatparya-tika I.1.1). As a criticism of the possibility and validity of all that claims to be knowledge, Nyaya is the pre-requisite to all methodical philosophizing (Arthashastra of Kautilya I.2). Kautiliya says that anviksiki (logic) is a separate branch of knowledge besides the other three – the Vedas, the science of commerce (varta), and polity (danda niti). Further, it is a light unto all other branches of learning.
Manu (Viii.43) and Gautama (ix), in their law codes,
prescribe a course in logic for monarchs. Those who mastered the science of
logic were preferred in the nomination of the members of law-making councils.
Vyasa is said to have classified the Vedas with the help of science of logic. The
Mahabharata (I 70.42, B.XII-210-22) mentions logic, saying that Narada was
familiar with the principles of reasoning. The word anvikshiki, which meant ‘the
science of inquiry’ came to be increasingly associated with ‘logic’.
Nilakantha, a commentator on the Mahabharata, explains it as ‘inference’. This is
because it is something which follows the perception (anu+iksha). Also known as
‘Tarka-vidya’, the anvikshiki is not to be indulged in just for the sake of unworthy
arguments.
In Devi Bhagavata Purana, Goddess Durga is called anvikshiki
because she induces the knowledge of the self in the seekers. The prime motive
of the science of anvikshiki (logic) is, like all schools of philosophy in
Hindu religion, moksha (liberation) through atma-vijnanam (self-knowledge). The
state of liberation can be achieved only through the knowledge of the entities
and their relative positions in the world.
Logic, as a system, was founded by Gautama, who is known as
Aksha-pada (one who has eyes towards his feet) and Dirgha-tapas (one of enduring
penance). He is believed to have been born around 550 BCE at Gautama-sthana in
Mithila. Gautama’s work, Nyayasutra, is perhaps, the first reduction of a
system of philosophy in the aphoristic style and is divided into five sections,
each consisting of two chapters. This work is the locus classicus of all
logical works, including a bhashya (commentary) by Vatsyayana and varttika
(gloss) by Uddyotakara. The logic of Gautama probably followed the exegetical
rules of reasoning of the Mimamsa School.
Nyaya, is both metaphysics and criticism, which are the
presuppositions of all metaphysics. Right means knowledge is the pre-requisite
of right discoveries regarding the world. Hence Nyaya specifies the right means
as – perception, inference, comparison and verbal testimony. Any cognition
involves the three factors of – the knower (Pramata), the known or knowable
(Prameya) and the means of knowledge (Pramana). Since this system of logic lays
more stress on epistemology, it is also known as Pramana Shastra. Nyaya insists
on the right definition (lakshana) as all topics in logic are enunciated,
defined and examined. It examines ideas like the nature of truth and regards practical
efficiency as the test for it. It enumerates that fallacies that may befall the
reasoning process. It ascertains the nature of mind, as the agency that
coordinates the materials of knowledge.
It tries to prove the existence of souls and their plurality
as well as the reality of the external world and demonstrates the existence of
God as a creator of the world from atoms. For this reason, it is paired with
the other system Vaiseshika, propounded by Kanada.
In its modern phase (from 900 CE), Nyaya developed into a
formal system of conceptual and linguistic analysis. Gangesha of Mithila (400
BCE) is the founder of the modern school (Navya-nyaya) at Navadvipa or Nuddea.
The methodology of this school has been used extensively even in the polemics
of the Vedanta systems.