Saññā and viññāna (perception and consciousness) may be differentiated as follows. Saññā (defined in Anguttara VI,vi,9 <A.iii,413>) is the quality or percept itself (e.g. blue), whereas viññāna (q.v) is the presence or consciousness of the quality or percept—or, more strictly, of the thing exhibiting the quality or percept (i.e. of nāmarūpa). (A quality, it may be noted, is unchanged whether it is present or absent—blue is blue whether seen or imagined --, and the word saññā is used both of five-base experience and of mental experience.)
It would be as wrong to say 'a feeling is perceived' as it would 'a percept is felt' (which mix up saññā and vedanā); but it is quite in order to say 'a feeling, a percept, (that is, a felt thing, a perceived thing) is cognized', which simply means that a feeling or a percept is present (as, indeed, they both are in all experience—see Majjhima v,3 <M.i,293>[15]). Strictly speaking, then, what is cognized is nāmarūpa, whereas what is perceived (or felt) is saññā (or vedanā), i.e. only nāma. This distinction can be shown grammatically. Vijānāti, to cognize, is active voice in sense (taking an objective accusative): consciousness cognizes a phenomenon (nāmarūpa); consciousness is always consciousness of something. Sañjānāti, to perceive, (or vediyati, to feel) is middle voice in sense (taking a cognate accusative): perception perceives [a percept] (or feeling feels [a feeling]). Thus we should say 'a blue thing (= a blueness), a painful thing (= a pain), is cognized', but 'blue is perceived' and 'pain is felt'. (In the Suttas generally, due allowance is to be made for the elasticity in the common usage of words. But in certain passages, and also in one's finer thinking, stricter definition may be required.)
At Dīgha i,9 <D.i,185>, Potthapāda asks the Buddha whether perception arises before knowledge, or knowledge before perception, or both together. The Buddha gives the following answer: Saññā kho Potthapāda pathamam uppajjati, pacchā ñānam; saññ'uppādā ca pana ñān'uppādo hoti. So evam pajānāti, Idapaccayā kira me ñānam udapādí ti. ('Perception, Potthapāda, arises first, knowledge afterwards; but with arising of perception there is arising of knowledge. One understands thus: 'With this as condition, indeed, knowledge arose in me.'') Saññā thus precedes ñāna, not only temporally but also structurally (or logically). Perception, that is to say, is structurally simpler than knowledge; and though perception comes first in time, it does not cease (see CITTA) in order that knowledge can arise. [a] However many stories there are to a house, the ground floor is built first; but it is not then removed to make way for the rest. (The case of vitakkavicārā and vācā—A NOTE ON PATICCASAMUPPĀDA §5—is parallel.)
The temptation must be resisted (into which, however, the Visuddhimagga [Ch. XIV] falls) to understand viññāna, in the primitive context of the khandhā, as a more elaborate version of saññā, thus approximating it to ñāna. But, whereas there is always consciousness when there is perception (see above), there is not always knowledge (which is preceded by perception). The difference between viññāna and saññā is in kind, not in degree. (In looser contexts, however,—e.g. Majjhima v,7 <M.i,317>—viññāna does tend to mean 'knowing', but not in opposition to saññā. In Majjhima xv,1 <M.iii,259-60>[16] & xiv,8 <227-8>[17] viññāna occurs in both senses, where the second is the complex consciousness of reflexion, i.e. the presence of a known phenomenon—of an example of a universal, that is to say.)
Footnotes:
[a] Cf. Bradley on judgement (op. cit. [Logic], T.E. II): 'I have taken judgement as the more or less conscious enlargement of an object, not in fact but as truth. The object is thus not altered in existence, but qualified in idea. ...For the object, merely as perceived, is not, as such, qualified as true.' And on inference (T.E. I): 'And our inference, to retain its unity and so in short be an inference, must...remain throughout within the limits of its special object.' 'Every inference, we saw, both starts with and is confined to a special object.' 'If, on the one hand, the object does not advance beyond its beginning, there clearly is no inference. But, on the other hand, if the object passes beyond what is itself, the inference is destroyed.' For Bradley, all inference is an ideal self-development of a real object, and judgement is an implicit inference. (For 'real' and 'ideal' we shall prefer 'immediate' and 'reflexive', at least in the first place.) This will scarcely be intelligible to the rationalist, who does not admit any experience more simple, structurally speaking, than knowledge. For the rationalist, moreover, all knowledge is explicitly inferential, whereas, as Sartre has pointed out (op. cit., p. 220), there is no knowledge, properly speaking, other than intuitive. Inference is merely instrumental in leading to intuition, and is then discarded; or, if intuition is not reached, it remains as a signpost. Rational knowledge is thus at two removes from perception (which, of course, is intuitive); and similarly with descriptive knowledge. Intuition is immediate contact between subject and object (see PHASSA); with the reflexive reduplication of intuitive knowledge (see ATTĀ [a] & MANO [b]), this becomes immediate contact between knowing (reflecting) subject and known (reflected) object; which, in the case of the arahat, is simply (presence of) the known thing. Cf. also Heidegger, op. cit., pp. 59-62 & 212-30. [Back to text]
