Source of the tensions
Dharmakīrti’s criterion for distinguishing pure sensation from judgmental conceptualizing is more multifaceted than Dignāga’s. What remains to be seen is why Dharmakīrti felt it necessary to introduce these complexities, which, if the above analysis is correct, led him into apparent contradictions. Let me offer a sketch of a possible answer.
Dignāga’s theory of cognition posited a radical distinction between two kinds of cognition. Sensation provides knowledge of particular sensible properties, while reason provides knowledge only of intellectible properties that are derived from sensible properties by ignoring subtle differences among sensibilia. This theory suggests that intellectible properties such as genera are not only derivative but also to some extent distorted, in that they involve some loss of information. A bulky male wrestler and a trim female gymnast may be regarded as belonging to the same genus only if all the sensible differences between them are factored out and discarded. This means that a general concept, for Dignāga, is always less rich in information than any given particular to which the concept might be applicable.
Given that concepts are therefore always in some sense weaker than the particulars to which they apply, it is not easy to see how a piece of reasoning could ever stand as a corrective to a raw experience. Dignāga’s radical division of cognitions into exactly two mutually exclusive classes would seem to favor an epistemological stance of radical empiricism, in which each moment of sensation validates itself and remains unassailable and ultimately incorrigible. Reason ultimately lacks the power to provide any new knowledge; at best, it can eliminate some interpretations of the sensible world that are logically contradictory to other interpretations. Moreover, reason lacks the force necessary to overturn the immediate intuitions of raw experience. If the perceiving mind feels like an enduring self witnessing a world of enduring substances that last for more than a moment, then there is no reason to doubt that feeling. The fact that an experience that simply feels as if it contravenes Buddhist doctrine is insufficient reason to reject the experience; if anything, it would be a reason to doubt the doctrine.
The doctrine of radical empiricism may have its virtues, but it is clear that the virtue of being easily reconciled with classical Buddhist doctrine is not among them. Each of the three classical formulations of the Buddha’s awakening, as was discussed earlier, involves the use of the intellect to arrive at a correct interpretation of the world of experience. In other words, if one is determined to defend the view that the doctrines of Buddhism are something more than a diluted and distorted account of an experience that was, in the final analysis, unique to the Buddha and utterly private and therefore unavailable to anyone else, then one must try to show why reason has the power to correct some of the false views that arise from poorly interpreted experience. By trying to construct a system of epistemology that placed an emphasis on the unique value of Buddhist doctrine, while also trying to maintain the appearance that he was offering a commentary on the works of Dignāga, Dharmakīrti created a philosophical system that was convoluted and perhaps even self-contradictory.
What seems to be the position of Dharmakīrti is that the experience of the person whose interpretation of his experience is consistent with the basic doctrines of Buddhism validates exactly those doctrines. Thus, insofar as one’s experiences confirm one’s confidence in the Four Noble Truths, the doctrine of non-self, and the doctrines of karma and rebirth, then one is, by Dharmakīrti’s standard, coming closer to the truth. While giving every appearance of trying to defend the doctrines of Buddhism by an appeal to experience and reason alone, independent of appeal to authority, Dharmakīrti ultimately makes a return to dogmatism.