Since the time Western scholars came to be interested in the study of Buddhism, we find various views expressed on the nature of early Buddhist thought, especially in comparison with the different trends in Western philosophy. One of the pioneers in this field, Professor T. W. Rhys Davids, whose main studies on Buddhism were confined to the Theravaada canon, especially the Paali Nikaayas consisting of the discourses attributed to the Buddha himself, pointed out at a very early date the relationship between Buddhism and the positivistic thought of the French philosopher Auguste Comte, where the claims of science received a full recognition.  Following this we find many scholars making random observations on the modernistic trends in Buddhism. For example, H. H. Price, speaking on the appeal of Hiinayaana Buddhism to the Western mind, wrote: "There are indeed some passages in the early part of the Questions of King Milinda which have a modern ring, and might almost have been written in Cambridge in the 1920's."  Of the scholars from the Orient, we find Radhakrishnan occasionally referring to the positivistic trends in early Buddhism.  All of these appear to be cursory glances at the nature of early Buddhism. None of these themes were worked out in full until Professor K. N. Jayatilleke made an exhaustive study of almost all the material, especially that embodied in the Paali Nikaayas, to show that early Buddhism compares with modern Empiricism, with the exception that unlike modern Empiricism, Buddhism recognized the validity of the data of extrasensory perception and of the experiential content of mysticism.  Professor Jayatilleke has examined most of the statements in the Paali canon embodying empiricist ideas, but a very important discourse, which could have been usefully utilized to prove his point of view, appears to have eluded him. It is a discourse included in the Sa.myutta Nikaaya,  and is called the "Discourse on 'Everything'" (Sabbasutta). Its AAgama version is found in the Chinese translation, the Tsa-a-han-ching. 
Eva.m me suta.m. Eka.m samaya.m Bhagavaa Saavatthiya.m viharati Jetavane Anaathapi.n.dikassa aaraame. Tatra kho Bhagavaa bhikkhuu aamantesi bhikkhave'ti.
1. Lectures on the Origin and Growth of Religion as illustrated by some points in the History of Indian Buddhism, The Hibbert Lectures, 1881 (London: Williams and Norgate, 1881), p. 31.
2. "The Present Relations between Eastern and Western Philosophy," The Hibbert Journal, LIII (April, 1955), 229.
3. Indian Philosophy (New York: The Macmillan Co., London: George Allen & Unwin Ltd., 1962), II, 472.
4. Early Buddhist Theory of Knowledqe (London: George Allen & Unwin Ltd., 1963).
5. Ed. M. Leon Feer (London: Pali Text Society, 1960), IV, 15.
6. Taishoo Shinshuu Daizookyoo, ed. J. Takakusu and K. Watanabe (Tokyo: Taishoo Issaikyo Kanko Kwai, 1924-1929), II, 91a-b.
Bhandante'ti te bhikkhuu Bhagavato paccassosu.m. Bhagavaa etad avoca. Sabba.m vo bhikkhave desissaami, tam su.naatha. Ki~n ca bhikkhave sabba.m. Cakkhu~n c'eva ruupaa ca, sota~n ca saddaa ca, ghaana~n ca gandhaa ca, jivhaa ca rasaa ca, kaayo ca pho.t.thabbaa ca, mano ca dhammaa ca. Ida.m vuccati bhikkhave sabba.m. Yo bhikkhave eva.m vadeyya, aham eta.m sabba.m paccakkhaaya a~n~na.m sabba.m pa~n~naapessaamiiti, tassa vaacaavatthur eva'ssa, pu.t.tho ca na sampaapeyya, uttari~n ca vighaatam aapajjeyya. Ta.m kissa hetu. Yathaa ta.m bhikkhave avisayasmin ti.
Thus have I heard. Once the Exalted One was living at Saavatthi, in the monastery of Anaathapi.n.dika (situated) in Jeta's Grove. Then the Exalted One addressed the monks: "O monks!" They responded: "Yes, O Lord!" and the Exalted One spoke thus: "Monks, I will preach to you 'everything'. Listen to it. What, monks, is 'everything'? Eye and material form, ear and sound, nose and odour, tongue and taste, body and tangibles, mind and concepts. These are called 'everything'. Monks, he who would say, 'I will reject this everything and proclaim another everything', he may certainly have a theory (of his own). But when questioned, he would not be able to answer and would, moreover, be subject to vexation. Why? Because it would not be within the range of experience."
Thus have I heard. Once the Buddha was staying in the country of `Sraavasti, in the monastery of Anaathapi.n.dika, situated in Jeta's Grove. At that time there was a Brahmin named Sheng-wen who came to the place where the Buddha was and greeted the Buddha. Having greeted the Buddha, he sat on a side and addressed the Buddha thus: "Gautama, (people) speak of 'everything'. What is the meaning of 'everything' ?" The Buddha addressed the Brahmin:" 'Everything' means the twelve 'gateways' (i.e., bases of cognition): eye, material form, ear, sound, nose, odour, tongue, taste, body, tangibles, mind and concepts. These are called 'everything'. Again, there may be those who say that this is not 'everything'. (They may say) 'That which the `Srama.na Gautama describes as everything, I will give up and proclaim another everything'. There could always be such a theory. But, if questioned, (he) would not know. It increases doubt and confusion. Why? Because it would not be within the range of experience." The Brahmin Sheng-wen listened to what the Buddha said and being pleased, went away.
The close similarity between these two versions cannot fail to impress the
reader. As far as the contents are concerned, there is hardly any difference between the two versions. The only difference is that in the Chinese version, the question as to what is meant by "everything" is put to the Buddha by a Brahmin named Sheng-wen, while in the Paali version, the Buddha himself raises the question and provides the answer. Sheng-wen is, no doubt, the Chinese rendering of the name Jaa.nusso.ni.  Jaa.nusso.ni is generally known to be a person who was interested in finding out the validity of some of the speculative theories current at the time. Once he is represented as questioning the Buddha regarding the two extreme views, namely, the Eternalist theory that "everything exists" (sabbam atthi), and the Materialist theory that "everything does not exist" (sabba.m n'atthi).  It is therefore natural that this discourse which purports to examine the basis of speculative theories, is presented as the Buddha's reply to a question raised by an interlocutor like Jaa.nusso.ni.
The importance of the above discourse as a locus classicus in any attempt to show the empircist trends in early Buddhism should be very evident. It does not deal with the problem of extrasensory perception and the speculation regarding the content of such experience. It only purports to reject all the speculative theories which go beyond the data of sensory experience. It refers to the twelve "gateways"  of cognition as the primary sources of our knowledge of empirical reality, and points out that any theory which goes beyond the data of sensory experience could lead to a lot of unnecessary speculation and diatribes resulting in vexation. The key word in the discourse is avisaya,  which represents a direct statement of the empiricist trend in early Buddhism.
7. Akanuma Chizen, Indo-Bukkyo Koyumeishi Jiten, Genshiki Hen (Nagoya: Haijinkaku Shobo, 1930-1931), pp. 240b-241b.
8. Sa.myutta Nikaaya, ed. M. Leon Feer (London: Pali Text Society, 1960), II, 76-77.
9. To use a term from modern psychology, vide Norman L. Munn, Psychology: The Fundamentals of Human Adjustment (4th ed.; London: George G. Harrap & Co., Ltd., 1961), p 507. The Chinese phrase 入處 , which literally means 'place of entry', is a rendering of the term aayatana. It has been noted that there is no English equivalent for the word aayatana, because aayatana refers to the sense organ as well as the object of sense. Vide Shwe Zan Aung, Compendium of Philosophy (London: Pali Text Society, 1963), p. 183, n 1.
10. The Chinese rendering is 非境界. This phrase occurs in the Chinese translation of the La^nkaavataara Suutra (vide Taishoo Shinshuu Daizookyoo, XVI, 524a) and the Sanskrit text (ed. Bunyiu Nanjio, Kyoto: Otani University Press, 1956) reads avi.saya (p. 49).