Universal and Necessary Judgements : Dharmakirti says that experience, positive and negative, can never produce a knowledge of the strict necessity of inseparable connection. It always reposes on the law of causation or on the law of identity. Experience provides to our Understanding all the materials for the construction of concepts. Sensible intuition by itself is but a chaos of distorted intuition. The understanding, besides constructing concepts, arranges them so as to give them order and systematic unity.
It produces synthesized bits of reality arranged as cause and effect, and a system of concepts delimited against one another, in the backdrop of the law of Identical Reference. The Law of Contradiction is implied as the principle of negative judgements. Thus the laws of
Contradiction, Causality and Identical Reference are the three laws which are the original possession of the Understanding.
These three laws are not derived from experience, they precede it and make it possible; they are necessary and universal truths. The realists( Nyaya school) deny strict necessity and universality in knowledge and they deny that the Understanding can be dissected into a definite number of its fundamental, necessary principles. All knowledge comes from experience which must be carefully examined. It can yield fairly reliable uniformities but a new, unexpected experience can upset our generalizations. Since all our knowledge without exception comes from experience, we cannot establish any exhaustive table of relations.
The Nyaya Vaisesika, Jaina, Mimansa, Sankhya share in the realistic view that the
Understanding represents initially a tabula rasa, comparable to the pure light of a lamp, that it contains no images and that there are no principles in the intellect before accidental
experience comes to fill it up with more or less accidental facts and rules.
The Buddhists maintain that there is a set of necessary principles which are not revealed by the lamp of experience but represent the lamp itself. The three laws are the weapons with which our understanding is armed before it starts on the business of collecting experience..
Limits of the Use of Pure Understanding:
Although the laws of Contradiction, Causality, and Identical Reference are the original possession of our Understanding and are independent in their origin from any sensible experience, they cannot extend their sway beyond the limits of experience. Those objects which by their nature lie beyond every possible experience, are metaphysical, are
unattainable as to the place in which they exist, as to the time at which they appear, as to the sensible qualities which they possess - such objects are uncognizable by the pure intellect.
The Problem of Negation : A non-existing or absent thing is a case of imagination; it can produce no sensation directly; but the positive thing which has produced the sensation can be interpreted by the intellect as involving the absence of another thing whose presence is thus denied. Negation is therefore never a direct or original attitude of the mind,as pure Sensation always is. Pure Sensation = pure affirmation. If we have a cognition of the type 'there is here no jar' or 'the jar is absent', the direct cognition viz., the visual sensation is produced by the empty place, not by the absent jar. The absent jar is a representation called forth by memory and constructed by the intellect; it is not perceived by the senses.
Negation is predominantly imagination. In marked opposition to the realists who maintain
"absence" is present , i.e, there is positive perception of an absent thing, the Buddhist asserts that "presence" is absent, i.e., there is negative perception of a present thing. The perception of an absent thing is impossible; it is a contradiction. If it is a case of perception, the thing is present, it cannot be absent. But how is it present ? It is present in the imagination and that means that all the conditions necessary for its perception are fulfilled. It would be necessarily perceived if it were present, but it is absent and therefore it is only imagined but not
perceived; it is perceived in imagination.
