Continued from Nagarjuna and Quantum Physics
We should be cautious about hastily translating the Sanskrit terms ‘pratityasamutpada’ and ‘sunyata’ before having understood the full spectrum of their meaning. Rather than dealing with the abstract term ‘pratityasamutpada’ and sunyata’, this essay will work with the images which Nagarjuna used to illustrate his concepts. The images are evidences of relations, intervals and intermediate states. 
Nagarjuna was the most significant Buddhist philosopher of India. He was the founder of the Middle Way School, Madhyamaka, which is of great topical interest because it became fundamental to all later Buddhist scholarly thought, known as Mahayana (Great Vehicle). It is a path of inner liberation which avoids the extreme views of substantialism and subjectivism. Apart from various unconfirmed legends, we have no assured biographical knowledge of Nagarjuna. The authenticity of thirteen of his works has been more or less established by research. The Danish scholar Lindtner has examined and translated these works into English. Nagarjuna's main work, Mulamadhyamaka-karika (MMK) has been translated into several European languages  In the MMK the Middle Way is described as:
“What arises dependently (pratityasamutpada) is pronounced to be substancelessness (sunyata). This is nothing but a dependent concept (prajnapti). Substancelessness (sunyata) constitutes the middle way”. [MMK: chapter 24, verse 18] Nagarjuna's view consists principally of two aspects. The first is an exposition of his view of reality (sunyata, pratityasamutpada), according to which reality has no firm core and does not consist of independent, substantial components. Reality is rather a system of two-bodies or many bodies which reciprocally affect each other . This view of reality is diametrically opposed to another key concept: ‘svabhava’, ‘own being’ or ‘inherent existence’, also known in the Greek tradition as ‘substance’.
The second aspect of Nagarjuna’s philosophy is an answer to the inner contradictions of four extreme modes of thought which can be subsumed under the headings: ‘substantialism’, ‘subjectivism’, ‘holism’ and ‘instrumentalism’. My thesis is that these four modes of thought are unsustainable.
Substance (or own being) is defined as something that has independent existence.  Substantialism is at the centre of traditional metaphysics, beginning with pre-Socratic philosophers, for example Parmenides and Heraclitus, who were two critics of substantial thought, and going right up to Immanuel Kant (1724-1804). Substance is considered to exist by itself, i.e. the unchangeable, eternal and underlying basis for the entire non-material foundation of the world in which we live. Plato (4th century BCE) made a distinction between two forms of being in his Parmenides: on the one hand, singular objects which exist exclusively through participation without own being and, on the other hand, ideas that do have own being. Traditional metaphysics adopted Plato’s dualism. An independent own being is characterised as something that, as an existing thing is not dependent on anything else (Descartes); is existing by itself and subsisting through itself (More); is completely unlimited by others and free from any kind of foreign command (Spinoza); and exists of itself without anything else (Schelling). The highest substance was often understood as God.
Since Kant's ‘Copernican Revolution’ the primary question of philosophy has no longer been to comprehend reality, but rather to fathom the mind, i.e. the source of perception and knowledge.
For this reason traditional metaphysics has lost ground in the modern world. In fact its central concepts, such as ‘substance’, ‘reality’, ‘essence’ and ‘being’ have been replaced by the reductionist modes of thought of modern science. Now ‘atoms’, ‘elementary particles’, ‘energy’, ‘fields of force’ and other concepts derived from the ‘laws of nature’ are viewed as the fundamental ground.
Subjectivism is the philosophical theory that all knowledge is subjective, and relative. According to René Descartes (1596-1650) consciousness is primarily existent and everything else is sheer content or form, a creation of consciousness. The summit of subjectivism is the idealism of George Berkeley (1685-1753). The subjectivism of Immanuel Kant can be considered as moderated idealism. Hans-Georg Gadamer (1900-2002) emphasises that subjectivity i.e. self-awareness has become the fulcrum of modern philosophical thought which provides us with evidential proof and certainty. This view has been continually brought into doubt by modern physical science. However, these doubts have not led to a new view of reality but to a fatal separation of philosophy and the sciences. This separation has exacerbated the dualism that preoccupies modern thought. Accordingly, the physicist P.C.W. Davies, expounds in his 1986 book that electrons, photons or atoms do not exist; they are nothing but models of thought. 
The third approach avoids the fatal either-or dichotomy of the first two approaches by merging subject and object into one entity, such that there are no longer any separate parts but only one identity: all is one. Holism is “the view that an organic or integrated whole has a reality independent of and greater than the sum of its parts”. ‘Wholeness’ is made absolute, is mystified and becomes an independent unity that exists without dependence on its parts. Wholeness is understood as something concrete as if it was a matter of fact or an object of experience. As a philosophical approach found in great periods of European history of philosophy, this view is connected with names like Thomas Aquinas (1224-1274), Leibniz (1646-1716) and Schelling (1775-1854). In quantum physics, holism is represented by David Bohm. His key concept is ‘holomovement’, an undivided wholeness in flowing movement. 
Instead of favoring subject or object or the two together, the fourth approach ignores the existence of the three. According to this viewpoint the search for reality is insignificant and meaningless. Instrumentalism is quite modern, intelligent (see the philosophy of Ernst Cassierer) and sometimes hair-splitting and hypercritical. It is difficult to disengage from it. It is an extension of subjectivism and it regards the process of thinking as model making and as working with information, without concern as to what phenomena the information is about. What philosopher Donald Davidson (1917-2003) said about subjectivism, might be true for instrumentalism also: “Once one makes the decision for the Cartesian approach, it seems that one is unable to indicate what one’s proofs are evidence for”. 
For instrumentalism, theories are not a description of the world but an instrument for a systematic classification and explanation of observations, and for the prediction of facts.
The instrumentalist approach is outlined by the experimental physicist Anton Zeilinger who stated in an interview, “In classical physics we speak of a world of things that exists somewhere outside and we describe their nature. In quantum physics we have learned that we have to be very careful about this. Ultimately physical sciences are not sciences of nature but sciences of statements about nature. Nature in itself is always a construction of mind. Niels Bohr once put it like this: ‘There is no world of quantum, there is only a quantum mechanical description’”. 
Nagarjuna presents these four extreme views of reality in a scheme that is called in Sanskrit: ‘catuskoti’, the equivalent of the Ancient Greek ‘tetralemma’, as follows: things have no substance: 1. neither out of themselves, 2. nor out of something else, 3. nor out of both, 4. nor without a cause. (tetralemma: a figure in Ancient Greek and logic with four possibilities.)This kind of tetralemma refutes the four modern views of reality as above mentioned. This shows that Nagarjuna does not fall into any of these extremes and that his view is completely up-to-date. In the very first verse of the MMK a tetralemma is pointed out: “Neither from itself nor from another, nor from both, nor without a cause, does anything whatever anywhere arise”.  This verse can be understood as the principal statement of the MMK: the refutation of the four extreme metaphysical views which cannot be reconciled with the dependent arising of things. If this is the case, the remainder of the MMK would be a clarification of this verse.
This requires careful examination. What is the assertion made by this verse? That nothing can be found, that there is nothing, that nothing exists?
Was Nagarjuna denying the external world? Did he wish to refute what evidently is? Did he want to call into question the world in which we live? Did he wish to deny the everywhere presence of things that somehow arise? If ‘to arise’ refers to the empirical data, then we are obliged to argue that if a thing does not arise out of itself, it must arise out of something else.
So we should ask: what is the significance of the notion ‘to arise’? In another text, Nagarjuna gives some indications how to understand this view. He writes in his Yuktisastika (YS): 19. “That which has arisen dependently on this and that that has not arisen substantially (svabhavatah). What has not arisen substantially, how can it literally (nama) be called 'arisen'? […] That which originates due to a cause and does not abide without (certain) conditions but disappears when the conditions are absent, how can it be understood as 'to exist'? 
By the notions of ‘to arise’ and ‘to exist’, Nagarjuna does not mean the empirical existence but the substantial existence, as we will see in the following examples. When in many passages of MMK Nagarjuna states that things do not arise (MMK 7.29), that they do not exist (MMK 3.7, 5.8, 14.6), that they are not to be found (MMK 2.25, 9.11), that they are not (MMK 15.10), that they are unreal (MMK 13.1), then clearly this has the meaning: things do not arise substantially.
They do not exist out of themselves; their independence cannot be found. They are dependent and in this sense they are substantially unreal. Nagarjuna only rejects the idea of a substantial arising of things which bear an absolute and independent existence. He does not refute the empirical existence of things as explained in the following: “It exists implies grasping after eternity. It does not exist implies the philosophy of annihilation. Therefore, a discerning person should not decide on either existence or non-existence”. (MMK 15.10)
For Nagarjuna, the expression ‘to exist’ has the meaning of ‘to exist substantially’. His issue is not the empirical existence of things but the conception of a permanent thing i.e. the idea of an own being, without dependence on something else. Nagarjuna refutes the concept of independent existence which is unchangeable, eternal and existing by itself. Things do not arise out of themselves, they do not exist absolutely and are dependent. Their permanent being or existence cannot be found. The many interpretations of Nagarjuna which claim that he is also refuting the empirical existence of objects, are making an inadmissible generalization which moves Nagarjuna near to subjectivism, nihilism and instrumentalism. Such interpretations originate in metaphysical approaches which themselves have a difficulty in recognizing the empirical existence of the data presented. This is not at all the case with Nagarjuna. Nagarjuna presents the dependence of phenomena mainly in images as in the twenty-five chapters of the MMK.
Meanings of pratityasamutpada.
In the first place pratityasamutpada is an indication of dependence. Dependent bodies are in an intermediate state, they are not properly separated and they are not one entity. Secondly, they rely on each other and are influenced or determined by something else. Thirdly, their behavior is influenced by something in-between, for example a mover is attracted by gravitational force, a viewer is dependent on rays of light between his eyes and the object, a piano player’s action is determined by the fine motor skills of his fingers, an agent is dependent on his act. Pratityasamutpada is an indication of dependence and of something that happens between the objects. One object is bound to the other without being identical to it. The implicit interpretations of pratityasamutpada, are in terms of time, structure and space.
The following citations and references illustrate the term pratityasamutpada. Pratityasamutpada is used:
1. as Dependence in Nagarjuna’s Hymn to the Buddha: “Dialecticians maintain that suffering is created by itself, created by (someone) else, created by both (or) without a cause, but You have stated that it is dependently born”. 
2. as an intermediate state by Nagarjuna: Objects are neither together nor separated (Nagarjuna, MMK 6. 10).
3. as bondage in the Hevajra Tantra: “Men are bound by the bondage of existence and are liberated by understanding the nature of existence”. 
4. as an intermediate state by Roger Penrose: “Quantum entanglement is a very strange type of thing. It is somewhere between objects being separate and being in communication with each other”. 
5. as something between bodies by Albert Einstein: “A courageous scientific imagination was needed to realize fully that not the behavior of bodies, but the behavior of something between them, that is, the field, may be essential for ordering and understanding events”. 
6. as the mean between things in modern mathematics: to quote Gioberti again: “The mean between two or more things, their juncture, union, transit, passage, crossing, interval, distance, bond and contact – all these are mysterious, for they are rooted in the continuum, in the infinite. The interval that runs between one idea and another, one thing and another, is infinite, and can only be surpassed by the creative act.
This is why the dynamic moment and dialectic concept of the mean are no less mysterious than those of the beginning and the end. The mean is a union of two diverse and opposite things in a unity. It is an essentially dialectic concept, and involves an apparent contradiction, namely, the identity of the one and the many, of the same and the diverse. This unity is simple and composite; it is unity and synthesis and harmony. It shares in two extremes without being one or the other. It is the continuum, and therefore the infinite. Now, the infinite identically uniting contraries, clarifies the nature of the interval. In motion, in time, in space, in concepts, the discrete is easy to grasp, because it is finite. The continuum and the interval are mysterious, because they are infinite”. 
 pratityasamutpada in Eastern and Western modes of thought.
 Lindtner, C. Nagarjuniana: Studies in the writings and philosophy of Nagarjuna. New Delhi: Motilal Banarsidass. 2002. It is worth noting, however, that Tilmann Vetter has raised doubts about the authenticity of one of Nagarjuna's works in: On the Authenticity of the Ratnavali. Asiatische Studien XLVI, 1992. pp. 492-506. For two well-known translations of MMK see: Kalupahana, D. J. Mulamadhyamakakarika Nagarjuna: The philosophy of the middle way. New Delhi: Motilal Banarsidass. 1999; Garfield, J. L. The fundamental wisdom of the middle way: Nagarjuna's 'Mulamadhyamakakarika'. New York: Oxford University Press. 1996. I use the expression 'body' synonymously with 'object' or 'particle' or 'field' or 'system' or 'entity'.
 Cf. Webster's New World Dictionary, Second College Edition, The World Publishing Company, New York and Cleveland. 1968. p. 669
 See: Gadamer, H.-G.. Der Anfang des Wissens. Phillip Reclam jun. Stuttgart 1999, p.35. Cf. Davies, P.C.W. and Brown, J.R. The Ghost in the Atom. Cambridge, University Press, 1986.
 Webster's New World Dictionary, Second College Edition, The World Publishing Company, New York and Cleveland. 1968.
 Cf. Bohm, D. Wholeness and the implicate Order. London: Routledge Classics. 2000.
 Cf. Davidson, D. The myth of the subjective. In: Davidson, D., Subjective, intersubjective, objective. New York: Oxford University Press. 1988 (my own translation from German).
 Zeilinger, A. Interview in the German newspaper Tagesspiegel 20th of December 1999 (my own translation). Steven Hawkings is defending a very similar position. He says: “I, on the other hand, am a positivist who believes that physical theories are just mathematical models we construct, and that it is meaningless to ask if they correspond to reality, just whether they predict observations”. Penrose, R. The Large, the Small and the Human Mind. In M. Longair (Ed.), The Objections of an Unashamed Reductionist. Cambridge: Cambridge University Press. 2000, p. 169. It is not meaningless to ask about the correspondence between a model and object, because if a model is correct then it has structural similarities with the phenomena that it is reconstructing; otherwise it can lead to predictions for which there are no meaningful physical explanation, because they have no correspondence to experimental data.
 Garfield, J. L. The fundamental wisdom of the middle way: Nagarjuna's Mulamadhyamakakarika' (MMK). New York: Oxford University Press. 1996, p. 3.
 See: Lindtner, C. op.cit., pp. 109 and 113.
 Images, metaphors, allegories or symbolic examples, analogical ideas, have a freshness which rational ideas do not possess. The starting point of the MMK is the double nature of phenomena. These fundamental two-body systems cannot be further divided analytically. The two bodies constitute a system of two material or immaterial components which complement each other. One of the components cannot exist without the other; each one forms the counterpart of the other.
 Nagarjuna, Catuhstava. Hymn to the Buddha. In: Lindtner, C. Nagarjuniana. New Delhi : Motilal Banarsidass. 1982. p. 135.
 Farrow, G.W. & Menon, I. The concealed Essence of the Hevajra Tantra. New Delhi: Motilal Banarsidass Publishers. 2001. p. 10.
 Penrose, R. The Large, the Small and the Human Mind. Cambridge: Cambridge University Press. 2000. p. 66.
 Einstein, A. & Infeld, L. The Evolution of Physics. London: Cambridge University Press. 1938, pp. 311-312.
 Gioberti, V. Della Protologia. Vol. 1. Náples: 1864, p. 160. In: Zellini, P. A brief History of Infinity. London: Penguin Books. 2005, p. 53.