Koan Zen and Wittgenstein’s Only Correct Method in Philosophy
Asian Philosophy Vol. 17, No. 3, November 2007, pp. 283–292
|Koan Zen is a philosophical practice that bears a strong family resemblance to Wittgenstein’s approach to philosophy. In this paper I hope to show that this resemblance is especially evident when we compare the Zen method of koan with Wittgenstein’s suggestion, towards the end of his Tractatus, about what would constitute the only correct method in philosophy. Both koan Zen and Wittgenstein’s method set limits to the reach of philosophical discourse. Each rules metaphysical speculation out of bounds. Neither, however, represents a rejection of the metaphysical. Where Wittgenstein enjoins silence in the face of the unsayable, a silence that allows the metaphysical to show itself, koan Zen calls for concrete demonstrations of that which cannot be captured in rational discourse. I attempt to illustrate this through discussion of a number of koans that serve as reminders that the philosopher (and Zen master) should say nothing except what can be said.
In this paper I hope to show that koan Zen represents a commitment to something like Wittgenstein’s ‘correct method in philosophy’ (Wittgenstein, 1978, 6.53). By ‘koan Zen’ I refer to that practice in certain schools of Zen Buddhism that consists in meditating on, under the guidance of a master, the apparently nonsensical statements and stories known in the Zen tradition as koans or ‘public cases’. Perhaps the best known example of a koan, at least outside the world of Zen, is Hakuin’s Sekishu or ‘One Hand’ koan, often inaccurately translated into English as ‘What is the sound of one hand clapping?’ Koan Zen, with its emphasis on ‘sudden enlight-enment’, presents a strong contrast with another Zen practice called shikantaza or ‘just sitting’. My claim is that koan Zen is a philosophical practice that is akin to Wittgenstein’s approach to philosophy, especially with regard to the limits he places on philosophical discourse.
What does Zen look like when approached as a philosophical practice? What does doing philosophy look like when approached as a Zen practice? My suggestion is that both look something like what Wittgenstein, towards the end of his Tractatus, describes as ‘the only strictly correct’ method in philosophy (Wittgenstein, 1978, 6.53). Wittgenstein writes:
Note that the injunction ‘to say nothing except what can be said’ seems to reduce philosophy to natural science. For only that which can be demonstrated to be either true or false—that is, the factual—can be expressed in propositional form. This is the sense of ‘saying’ in Wittgenstein’s usage. But Wittgenstein has already said that ‘Philosophy is not one of the natural sciences’ (1978, 4.111). Limited to saying what can only be said in the ‘propositions of natural science’, the philosopher’s other task is to demonstrate to anyone who tries to say something metaphysical ‘that he had failed to give a meaning to certain signs in his propositions’ (1978, 6.53). According to this view, philosophy’s proper role would seem to consist in policing the border between what can, and what cannot, be said. This, Wittgenstein admits, would not feel like doing philosophy (1978, 6.53). But it does feel like Zen. For an important task of the Zen philosopher is to police the border between the factual and the non-factual, between the sayable and the non-sayable, between the contingent and the necessary. But this task cannot be reduced to just policing. The Zen master must somehow point the disciple to the realm of the non-sayable while at the same time keeping him or her firmly anchored in the sayable. When questioned about whether a dog has Buddha nature or not, Joshu shouts ‘No!’ (Sekida, 1995, p. 27).It might be objected that there is something distasteful in ascribing a policing role to either philosopher or Zen master. But whether the image used is that of policing, or gate-keeping, or border control, it is in keeping with the rhetoric of Zen. See, for example, the following words of Mumon: ‘In order to master Zen, you must pass the barrier of the patriarchs’ (Sekida, 1995, p. 27). Now, as Robert Aitken observes, the word ‘barrier’ here has the connotation of ‘check point at a frontier’ (Aitken, 1990, p. 11). Aitkin says further that ‘in Zen Buddhist practice someone in a little house by the road will say: ‘‘Let me see your credentials. How do you stand with yourself ? How do you stand with the world?’’ You present yourself and are told: ‘‘Okay, you may pass’’ or ‘‘No, you may not pass’’’ (Aitkin, 1990, p. 11). The ‘someone in the little house by the road’ is, of course, the Zen master in dokusan (private interview) who tests the attainment of the disciple. The master is, in effect, policing the border between what can be said and what cannot be said, the border between the disciple’s confused and ignorant attempt to say the unsayable, and the insightful recognition that all that is essential lies beyond the reach of language and thought.
What is the status of Wittgenstein’s statement about the ‘correct method’, given that it would seem to be contradicted in the Philosophical Investigations where Wittgenstein writes: ‘There is not a philosophical method, though there are indeed methods, like different therapies’ (Wittgenstein, 1981, para. 133)? Clearly, it is not a proposition of natural science. Nor is it an attempt to say something metaphysical. Perhaps it is a rung in the Tractarian ladder that is to be climbed and then discarded (Wittgenstein, 1978, 6.53). If this statement, too, is to be revealed as nonsensical, then it could be read as a demonstration of the irony that underlies the Tractarian view of philosophy and its methodology—an irony that might have much in common with the Buddha’s silent response to the non-Buddhist philosopher who said to him ‘I do not ask for words; I do not ask for non-words’. Or it could be read as an example of Wittgenstein’s readiness to use what Gordon Bearn calls a ‘metaphysical poison (nonsense/Unsinn) to end the explanatory metaphysical impulse’ (Bearn, 1997, p. 58).
Notice the qualification in what Wittgenstein says about the ‘correct method’. He writes: ‘The correct method in philosophy would really be the following’ (1978, 6.53). This suggests an ideal to be aimed at, approximated to, but seldom, if ever, attained—perhaps because its use would not feel like doing philosophy. So although Wittgenstein formulates his so-called only strictly correct method in doing philosophy, it is clear that he does not follow this method himself in his Tractatus. Thus Gordon Bearn can sketch the metaphysics of the Tractatus as follows:
Bearn’s sketch of the Tractarian metaphysics calls to mind Victor Sogen Hori’s account of the undifferentiated/differentiated world of Zen (Hori, 2003, pp. 20–21). Bearn bases his sketch on the following propositions from the Tractatus: ‘Objects, the unalterable, and the subsistent are one’ (2.027); ‘(Ethics and aesthetics are one)’ (6.421); ‘The world and life are one’ (5.621). Bearn comments: ‘The metaphysics of the Tractatus are designed to be the last metaphysics, they are designed to destroy the impulse to speak what must not be spoken’ (Bearn, 1997, p. 76). Now what Bearn says about the Tractarian metaphysics could be applied to the Zen koans in that it would seem that ‘they are designed to destroy the impulse to speak what must not be spoken’. Yet, unlike the Tractatus, they do this without even a masked attempt to formulate a metaphysics. True to what, according to Wittgenstein, is the only strictly correct method in philosophy, they insist that the practitioner ‘say nothing except what can be said’ (Wittgenstein, 1978, 6.53). Note, in passing, that when Zen commentators, Victor Sogen Hori for example, speak of the ‘undifferentiated/differentiated realms’, they do so outside the language-game of koan Zen.
The koan master’s consistent refusal to formulate metaphysical propositions is not put off by feelings about whether one is doing, or not doing, philosophy, or even Zen. The claim that Zen represents a commitment to something like Wittgenstein’s ‘strictly correct method in philosophy’ is based on its refusal to entertain any metaphysical doctrine. For Zen is a deliberate and rigorous turning away from the metaphysical speculations of the Mahayana. Attempts to explicate and articulate what is thought to be Zen’s hidden philosophical potential only serve to betray Zen by returning it to metaphysics. Zen, if looked at through the lens of Wittgenstein’s philosophy, does not need to deck itself out in the disputed doctrines of metaphysics in order to prove its philosophical credentials. Nevertheless, this does not mean that Zen is anti-metaphysical. Rather it is a case of refusing to engage in metaphysical speculations or to argue the merits of a metaphysical position. The Zen master lets the metaphysical manifest itself in whatever concrete individual act or thing is to hand. Careful attention to the koan and how it works will show that this is so. ‘A monk asked Ummon, ‘‘What is Buddha?’’ Ummon replied, ‘‘A dried shit-stick!’’’ (Sekida, 1995, p. 77).
There are surely grounds for objecting to the view that Zen can—even must—do without metaphysical speculation or adherence to metaphysical doctrines. Consider the relation between theory and practice. It is almost commonplace now to remark that theory without practice is sterile, while practice without theory is blind. Is it possible to practice philosophy, or Zen, in a doctrinal or theoretical void? For example, does not a commitment to the Zen practice of shikantaza (just sitting in silent meditation) presuppose a belief in the inherent Buddha nature? And does not a commitment to koan meditation presuppose a belief that the inherent Buddha nature is to no avail unless it is realised in the enlightenment experience?
Can a distinction be drawn between a speculative metaphysics and an experiential metaphysics? Does the rejection of speculation entail the rejection of metaphysics? Can Zen be expected to provide answers to such questions? Or is Zen concerned not so much to answer questions as to create the conditions that will allow the answers to emerge? A philosophy that does not answer questions? Consider Wittgenstein’s remark that ‘a philosophical treatise might contain nothing but questions (without answers)’ (Sorensen, 2003, p. 340).
The 13th-century Zen master Mumon Ekai used koans as brickbats, as he said, to batter the gate that bars entry to the way of Zen. This gate might be thought of as ‘the impulse to speak what must not be spoken’. This impulse calls to mind Mumon’s ‘striking at the moon with a stick’ (Sekida, 1995, p. 26), or ‘scratching a shoe, whereas it is the foot that itches’ (Sekida, 1995, p. 26). That is to say, in Zen there is a recognition of the incommensurability between the metaphysical impulse and what it seeks to express in the form of the propositions of philosophy or, as Mumon would put it, ‘other people’s words’ (Sekida, 1995, p. 26). Mumon warns his disciples not to confuse their ‘own treasures’ (Sekida, 1995, p. 26)—their own realisation of the metaphysical—with the ‘things coming in through the gate’ (Sekida, 1995, p. 26), namely, the speculations of others. That is, he attempted, with the help of the cases of the ancient masters or, in other words, koans, to awaken his monks to the fact that nothing, nothing at all, stood in the way of their full possession of the present moment of their daily lives. This nothing-gate-barrier was no more than a picture, a figment of the imagination, a product of conventional habits of thought. He might have pointed out to them that they were held captive by nothing but a picture. As Wittgenstein would say: ‘A picture held us captive. And we could not get outside it, for it lay in our language and language seemed to repeat it to us inexorably’ (Wittgenstein, 1981, para. 115). So might it not be the case that those who have difficulty in seeing that the practice of Zen is a philosophical practice are likewise held captive by a picture? And is this not a somewhat narrow and misleading picture of the nature and practice of philosophy, especially when viewed against the backdrop of the whole history of Western philosophy? Here it might be well to recall the koan that asks: ‘Why is it that a man of great strength cannot lift his legs?’ (Sekida, 1995, p. 75). But why raise this koan question in this context? Because an inability to freely respond here may very well indicate that the practitioner is held fast by the picture suggested in the koan of a strong man bound. What is exemplified in the failure to solve this koan is the binding (blinding!) power of the image that it conjures up in the imagination of the practitioner. It is a perfect example of the captivating power of the picture that, says Wittgenstein, ‘lay in our language’.
It might be objected that koan language, in that it makes use of whatever is to hand, is too blunt an instrument to be identified with Wittgenstein’s only correct method in philosophy. Surely, it will be pointed out, Wittgenstein’s method does not envisage using just anything, but rather the precise identification of the misuse of a sign. Such an objection, however, would be based on a misreading of what has been said about the relation of the koan method to what Wittgenstein suggests would be the only correct method in philosophy. So perhaps it needs to be emphasised that at no point have the two methods been identified. Rather, it was said that koan Zen can be likened to a commitment to something like Wittgenstein’s correct method. In that it serves to awaken the practitioner to both the realm of the metaphysical and to the impossibility of capturing the metaphysical in propositional language, it is true to the intent of Wittgenstein’s correct method. But if Wittgenstein’s method requires the precise identification of the misuse of a sign, then the koan might be too blunt an instrument. But this gives rise to the question: does Wittgenstein’s method demand a precise identification of the misuse of a sign? The answer would seem to be in the negative in that what Wittgenstein calls for is a ‘demonstration’ that the would-be metaphysician has ‘failed to give a meaning to certain signs in his propositions’ (Wittgenstein, 1978, 6.53). There is no mention here of precision or exactly how the demonstration is to be carried out. And here it must be remembered that the appropriate response to a koan is always a demonstration. In its family resemblance to Wittgenstein’s only correct method in philosophy, the koan method would seem to be more like than unlike.Not unrelated to Wittgenstein’s only correct method in philosophy is his declaration, in the Investigations, that ‘[t]he work of the philosopher consists in assembling reminders for a particular purpose’ (Wittgenstein, 1981, para. 127). Given the brevity and starkness of Wittgenstein’s assertion, it is clear that here he is not
interested in saving his readers the trouble of thinking for themselves. As he says in the preface to the Philosophical Investigations: ‘I should not like my writing to spare other people the trouble of thinking. But, if possible, to stimulate someone to thoughts of his own’. Like the Zen koan, Wittgenstein’s assertion that the work of the philosopher ‘consists in assembling reminders for a particular purpose’ must challenge many of the familiar certainties about the ‘what’ and the ‘how’ of philosophy. And so, thinking for myself, I would suggest that the particular purpose for which we are to be reminded is the commitment to saying nothing except what can be said.
Perhaps it could be said that the work of the Zen master, like that of Wittgenstein’s philosopher, ‘consists in assembling reminders for a particular purpose’. For just as Wittgenstein does not wish ‘to spare other people the trouble of thinking’, so the Zen master has no intention of sparing his or her disciple the trouble of personal inquiry. Yet Zen inquiry is pursued, not through thinking, but through a carefully practised discipline of non-thinking, a practice that is learnt and perfected through meditation on koans.
But if the Zen master’s work could be represented as ‘assembling reminders for a particular purpose’, would this be the same as Thomas Cleary’s ‘[r]ecollections of koans’, a recollection that ‘facilitates the ongoing practice of Buddhist meditations in the midst of ordinary worldly activities’ (Cleary, 1997, p. xii)? It would seem not, given Cleary’s view of the koan as an ‘objective example’ that functions ‘like a technical formula, a design, representing Buddhist teaching in a highly concentrated form’ (Cleary, 1997, p. xii). The Zen master’s reminders are not of doctrine but of a strategic practice. This is the practice that corresponds with Wittgenstein’s ‘correct method in philosophy’, the method of saying nothing ‘except what can be said’.
In reminding the disciple ‘to say nothing except what can be said’, the Zen master must be able to demonstrate to any disciple ‘who wanted to say something metaphysical . . . that he had failed to give a meaning to certain signs in his propositions’. In Zen such a demonstration might take the form of a curt dismissal: ‘If you mention Buddha nature here I will throw you out!’ But still the master will demand that the disciple ‘say something’. However, the ‘saying’ that is required is not an ordinary saying—the formulation of a proposition—but a ‘showing’.
It might be objected here that it is difficult to accept that there is an analogy between Wittgenstein’s method and that of the Zen master in that whereas Wittgenstein is at pains to avoid saying what cannot be said—or to point out the nonsensicality of all attempts to say the unsayable—Zen, with its nonsensical koans, insists on saying what cannot be said, insists on speaking nonsense, in order to effect a switch in the disciple to a rejection of what cannot be said. However, it needs to be stressed that Zen does not reject what cannot be said. Moreover, the nonsensical character of koan language is only apparent. Once the grammar of this language-game has been mastered, the nonsensical appearance of its language is seen through.
As Wittgenstein’s philosopher is to assemble reminders for a particular purpose, so must the Zen master. The reminders do not function in terms of a fully articulated theoretical system. Rather, they come into play in response to particular needs and particular problems in particular situations—such as ‘whenever someone . . . wanted to say something metaphysical’.
It could be said that one of the reasons a Zen master utilises koans is to remind the disciple of both the power and the limitations of language. The disciple is challenged to demonstrate his or her freedom in the use of language. That is, while respecting the limits of language, the disciple must be able to exploit its resources to the full—to say clearly what can be said, to show what cannot be said, and to be silent when and where appropriate. The Zen master uses koans both to remind the disciple to limit saying to the sayable, and to challenge the disciple to show the unsayable. Speak! Speak!
The Zen practitioner following a koan curriculum will find that the shokan or ‘First Barrier’ koans, that lead into the realm of what some commentators call ‘the Undifferentiated’—a term that would not be accepted in the context of dokusan— are usually followed by a selection of 22 koans in 57 parts known as the ‘Miscellaneous Koans’ (Yamada, 1988). These might be regarded as so many reminders to the practitioner that what has been realised in the shokan koans is not separate from ordinary, everyday life. It would seem that the practitioner, who has experienced the overcoming of dualism through intense inquiry into Joshu’ ‘Mu’ and Hakuin’s ‘One Hand’, must now be trained by means of an engagement with these many and varied koans, which function as so many reminders, not to create a new dualism of the ‘Undifferentiated’ and the ‘Differentiated’. The practitioner needs to be reminded that ‘the Way of the Enlightened’ is ‘not one, not two’. The Zen master, of course, does not engage with this ‘not one, not two’ at the theoretical level. Rather, the master’s engagement is practical in that he or she trains the disciple to recognise the ‘not one, not two’ in every set of ‘two’ that presents itself in the ordinary and familiar events of everyday life and feeling and thinking.
Let me give some examples. In the first of ‘Miscellaneous Koans’ (Yamada, 1988, pp. 1–7), the practitioner is directed to ‘Stop the sound of the distant temple bell’. This koan would seem to place the practitioner in a space marked by the radical differentiation of dualism. But against the dualism that radicalises and absolutises the evident fact of duality, the koan draws the meditator into an awareness of the bond that exists between perceiver and perceived. It achieves this purpose when the one who hears and listens to the sound of the distant temple bell becomes so attentive to that sound that all sense of a separate self is lost. At last there is only the sound of the temple bell, a sound that the meditator, when challenged in dokusan, will spontaneously and unselfconsciously echo.
The Zen practitioner is not concerned with saying what being one with the sound of the temple bell, or indeed with all things, might mean. The Zen concern is to be aware of, to be minded of, to be re-minded of, to realise, the common bond that holds all things together. In this realisation the Zen practitioner can respond appropriately to such koan demands as the following: ‘Make Mount Fuji take three steps’, ‘Put out the fire a thousand miles away’, ‘Stop the boat sailing by on the open sea’, ‘Show an immoveable tree in a fierce storm’.
A philosophical practice that consists in assembling reminders not to attempt to say the unsayable, as exhibited in the ‘Miscellaneous Koans’, does not lead to the discovery of anything new. Compare what Wittgenstein says about logical investigation that does not aim ‘to hunt out new facts’ (Wittgenstein, 1981, para. 89). The whole point here, for Wittgenstein, is that ‘we do not seek to learn anything new by it’ (para. 89). As he says: ‘We want to understand something that is already in plain view’ (para. 89). And he distinguishes what takes place here from the way questions are pursued in the natural sciences. He adds: ‘Something that we know when no one asks us, but no longer know when we are supposed to give an account of it, is something that we need to remind ourselves of ’ (para. 89). Yet clearly Wittgenstein does not regard this as an easy task. As he says, and he puts this in brackets: ‘(And it is obviously something of which for some reason it is difficult to remind oneself)’ (para. 89). And so the Zen master challenges the disciple with a koan the answer to which ‘is already in plain view’. This koan, which does not look like a koan, declares: ‘The principle of Zen is complete freedom’.
The koan that declares the principle of Zen to be complete freedom must constitute a genuine challenge for any practitioner with a philosophical bent. For how, it might be wondered, will such a one fail to rise to the bait that links such ideas as ‘the principle of Zen’ and ‘complete freedom’? The tendency of the philosophically minded disciple-practitioner is to gnaw at these ideas as the proverbial dog gnaws at its bone. But Zen is not about ideas. It is always about what is right there in front of each and every Zen practitioner. Speculation about freedom, about what might be meant by complete freedom, and about whether such a state is either possible or desirable, cannot but frustrate the disciple’s engagement with this koan. For this koan is to be responded to in terms of the practitioner’s very own concrete situation. The Zen practitioner’s concern is with the exercise of freedom rather than with its definition.
The philosophical practice of Zen is the implementation of an exercised knowledge—a knowing how—not to be confused with the elaboration of a theoretical system of knowledge in which definitions and propositions find their home. Exercised knowledge is a ‘knowing how’ that demonstrates itself in right practice, that is, a practice that is appropriate to the task in hand. Appropriateness here is the fit between the practical insight and judgement of the practitioner and the requirements of what is to be done.
Does Zen philosophy treat of freedom? It might be thought that it should, given that not only does it represent itself as a path to liberation, but it also has this koan that asserts ‘The principle of Zen is complete freedom’. However, intellectual and scholarly approaches to the koan tend to forget that meditation on a koan is never just a mental exercise. For it directly involves the practitioner’s body. The meditator must incorporate (incarnate) the koan. Of particular significance here is the fact that he or she sits, not in a lounge chair, but in a yoga asana. The sitting posture prescribed for zazen requires the meditator to actively sit and not to passively lounge. Meditation on a koan is as much about body awareness, and breath awareness, and awareness of the meditation environment, as it is about the specific topic of inquiry.Given, then, the system of physical, psychological, social, and environmental constraints within which the Zen practitioner meditates on the ‘complete freedom’ of
Zen, the appropriate koan response here cannot but acknowledge the experience of these many and varied limitations. So the challenge for the disciple consists in this; while avoiding a theoretical exposition, to manifest to the master how the complete freedom of Zen is experienced, understood, incorporated, and expressed in the ordinary, everyday life situation of this self-same disciple.
The koan about freedom neither argues nor explains. It appears as a simple assertion that, at the level of Wittgenstein’s factual propositions, must be declared nonsensical. But as an assertion can it escape the charge of being nonsensical and empty? Wittgenstein would seem to think so. He writes that ‘we can avoid ineptness or emptiness in our assertions only by presenting the model as what it is, as an object of comparison – as, so to speak, a measuring-rod; not as a preconceived idea to which reality must correspond’ (Wittgenstein, 1981, para. 131). So how might the notion (model) of complete freedom serve as a measuring-rod? The disciple takes this koan and, instead of attempting to speculate about freedom, sets it as a measuring-rod against the fabric of his or her own life. Letting go of any dogmatic preconception of what constitutes ‘complete freedom’, the practitioner-disciple attends to the actuality of that which presents itself. Does the measured alter the measure here? It seems that it must if, in Wittgenstein’s words, ‘[t]he dogmatism into which we fall so easily in doing philosophy’ (Wittgenstein, para. 131) is to be avoided.
If koan Zen is a philosophical practice, it would seem to follow that it must deal with philosophical problems, such as the problem of freedom, and do so philosophically. But how can it do this if it neither argues nor explains? Consider the following remark by Wittgenstein:
So looking into the workings of koan language, it appears that even when a koan takes the form of an assertion, this is not to be reverenced as dogma but is to be tested in life. Theory, hypothesis, speculation about the unsayable, argument, and explanation are all set aside. The practitioner must not be taken in by words, least of all by the words of a koan. He or she must do constant ‘battle against the bewitchment of our intelligence by means of language’. The words of the koan must be tested and understood in the light of what the practitioner has always known. Koans, such as those found in the ‘Miscellaneous Koans’, do not provide the Zen practitioner with any new information. Instead, they re-direct the practitioner’s attention, bring his or her mind back, to the always already known. This ‘always already known’ is the knowledge that is exercised in sitting still, breathing in, breathing out. It entails a respectful silence in the presence of what cannot be said but only shown. Hungry? Have something to eat. Tired? Take a nap.
Aitkin, R. (1990). The Gateless Barrier: The Wu-Men Kuan (Mumonkan) (R. Aitken, Trans. and commentary). San Francisco: North Point Press.
Bearn, G. C. F. (1997).Waking to Wonder: Wittgenstein's Existential Investigations . Albany, NY: State University of New York Press.
Cleary, T. (1997). Kensho: The Heart of Zen . Boston and London: Shambhala.
Hori, V. S. (2003).Zen Sand: The Book of Capping Phrases for Koan Practice Compiled, translated, and annotated by V. S. Hori. Honolulu: University of Hawai’i Press.
Sekida, K. (1995). Two Zen Classics: Mumonkan and Hekiganroku (K. Sekida, Trans. and commentary). Edited and introduced by A.V. Grimstone. New York and Tokyo: Weatherhill.
Sorensen, R. (2003). A Brief History of the Paradox: Philosophy and the Labyrinths of the Mind . Oxford: Oxford University Press.
Wittgenstein, L. (1978). Tractatus logico-philosophicus. The German text of Logisch -philosophische Abhandlung, (D. F. Pears & B. F. McGuinness, Trans.). Introduction by Bertrand Russell. London and Henley: Routledge & Kegan Paul.
Wittgenstein, L. (1981). Philosophical Investigations (G. E. M. Anscombe, Trans.). Oxford: Basil Blackwell.
Yamada, K. (1988). Course of Koan study (rev. September 1988 by M. Sato & P. Shepherd with the help of R. Stone & J. Lucyshyn) (new edn 1989). Dietfurt: Meditationshaus St Franzisku. [Adapted in Bodhi Sangha Koans, Bodhizendo, May 2004
Chung-ying Cheng: On Zen (Ch’an) Language and Zen Paradoxes
James D. Sellmann & Hans Julius Schneider: Liberating Language in Linji and Wittgenstein
Dale S. Wright: Rethinking Transcendence: The Role of Language in Zen Experience