n the same plane as that in which many physical phenomena
are produced [Footnote ref 2].

The four Prama@nas of Nyaya.

We know that the Carvakas admitted perception (_pratyak@sa_)
alone as the valid source of knowledge. The Buddhists and the
Vais'e@sika admitted two sources, pratyak@sa and inference (_anumana_);
Sa@mkhya added _s'abda_ (testimony) as the third source;

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[Footnote 1: See _Nyayamanjari_, pp. 12-26.]

[Footnote 2: Discussing the question of the validity of knowledge Ganges'a,
a later naiyayika of great fame, says that it is derived as a result of
our inference from the correspondence of the perception of a thing with
the activity which prompted us to realize it. That which leads us to
successful activity is valid and the opposite invalid. When I am sure
that if I work in accordance with the perception of an object I shall be
successful, I call it valid knowledge. _Tattvacintama@ni_, K.
Tarkavagis'a's edition, _Prama@nyavada_.

"The _Vais'e@sika sutras_ tacitly admit the Vedas as a prama@na. The view
that Vais'e@sika only admitted two prama@nas, perception and inference, is
traditionally accepted, _"pratyak@sameka@mcarvaka@h ka@nadasugatau puna@h
anumananca taccapi,_ etc." Pras'astapada divides all cognition (_buddhi_)
as _vidya_ (right knowledge) and _avidya_ (ignorance). Under _avidya_ he
counts _sa@ms'aya_ (doubt or uncertainty), _viparyaya_ (illusion or
error), _anadhyavasaya_ (want of definite knowledge, thus when a man who
had never seen a mango, sees it for the first time, he wonders what it
may be) and _svapna_ (dream). Right knowledge (_vidya_) is of four kinds,
perception, inference, memory and the supernatural knowledge of the sages
(_ar@sa_). Interpreting the _Vais'e@sika sutras_ I.i. 3, VI. i. 1, and VI.
i. 3, to mean that the validity of the Vedas depends upon the trustworthy
character of their author, he does not consider scriptures as valid in
themselves. Their validity is only derived by inference from the
trustworthy character of their author. _Arthapatti_ (implication) and
_anupalabdhi_ (non-perception) are also classed as inference and _upamana_
(analogy) and _aitihya_ (tradition) are regarded as being the same as
faith in trustworthy persons and hence cases of inference.]

333

Nyaya adds a fourth, _upamana_ (analogy). The principle on which
the four-fold division of prama@nas depends is that the causal
col