15th July 2013
Is Ayurveda scientific in a meaningful way? No. It has no capacity to grow.
Before examining claims about "vedic science" more generally I want to dwell on the more obvious branch of vedic science – ayurveda.
In this post I want to examine whether Ayurveda is scienctific in any real sense of the word (meaning scientific in approach towards its theory building and evolution as science).
I do so by annotating extracts from a peer reviewed journal article (download the full article here, Word verion here.). I agree with the author Engler that Ayurveda is NOT scientific. It has no innate ability to grow and improve itself since it does not test its hypotheses. It can be called proto-scientific but not scientific.
An actual scientific method has the ability to REJECT theories which don't work. Ayurveda has no such capacity and its proponents must assume a number of things without proof, like in any religion.
"Science" vs. "Religion" in Classical Ayurveda, by Steven Engler, Numen, Vol. 50, Fasc. 4 (2003), pp. 416-463
Summary This paper evaluates claims that classical Ayurveda was scientific, in a modem western sense, and that the many religious and magical elements found in the texts were all either stale Vedic remnants or later brahminic impositions. It argues (1) that Ayurveda did not manifest standard criteria of "science" (e.g., materialism, empirical observation, experimentation, falsification, quantification, or a developed conception of proof) and (2) that Vedic aspects of the classical texts are too central to be considered inauthentic or marginal.
The status of science in non-western cultures is a small but growing sub-field of the study of relations between science and religion. Ayurveda, the ancient South Asian medical tradition, provides a useful case study. This paper examines a variety of claims that Ayurveda was truly empirical, rational, or scientific and that elements of religion and magic in the texts were minor, non-essential, or inauthentic.
Several scholars argue that Ayurveda was scientific and that the many religious and magical elements found in the texts were either stale Vedic remnants or later brahminic impositions that sought to repress Ayurveda's revolutionary empiricism:
"In a tradition dominated by the pundits, Ayurveda … represent[s] the seeds of secular thought. True, this secularism is almost immediately repressed, normalized, impregnated with a religious vocabulary" (Zimmermann 1987:212).
Debiprasad Chattopadhyaya argues that "In ancient India, the only discipline that promises to be fully secular and contains clear potentials of the modem understanding of natural science is medicine"; and he claims that the "magico-religious" aspects of the texts are "alien elements" and "later grafts" (1977:2-4; cf. 1986:30-35).
G. Jan Meulenbeld suggests that brahminic domination is the reason that Ayurveda was unable to pursue its empirical course of modifying theories in the light of observed anomalies (1987:4-5).
For Kenneth Zysk, remnants of magical elements attest to Ayurveda's Vedic origins, and a veneer of brahminic elements attest to the "hinduization process" that brought it into the fold of orthodoxy (1991:118).
According to these views, the classical texts consist of distinct layers: authentic Ayurveda – empirical, rational, and scientific – and one or more inauthentic and ill-fitting religious strata.
Several characteristics of science play a role in these claims: (1) reductive materialism in the characterization of health and disease, the make-up of the human body, and the function of medicinal substances; (2) the role of empirical observation and inference in diagnostic practice and as a factor in theory modification; (3) theoretical rationality as indicated both by a formal conceptualization of anomalies and by a non-deterministic view of action (situating empirical therapeutics within a more open sense of "karma"); and (4) evidence of rudimentary professionalization among ayurvedic physicians.
The first section of the paper offers a brief overview of Ayurveda [Sanjeev: I've deleted it], and the second section considers claims that the tradition was scientific and finds these claims to be untenable. The weaker claim that Ayurveda had certain empirical characteristics is well supported.
Ayurveda as Science
Recent claims that Ayurveda was scientific are explicit that "science" is to be taken here in terms of "the modem understanding of natural science" (Chattopadhyaya 1977:2; cf. Zimmermann 1987:212; Meulenbeld 1987:4-5). This section considers several ways in which Ayurveda might appear, at first sight, to be scientific in this narrow sense: materialism, empirical observation, experimentation, falsification of theories, quantification, a developed conception of proof, and two specific logical concepts (prabhava and yukti). The purpose of this section is to measure Ayurveda by this modem western definition of science, in order to evaluate claims that it does, in fact, meet this definition.
A close reading of the texts leads to the conclusion that Ayurveda was not properly scientific according to these criteria, though it was empirical, i.e., observation-based, in more general ways that would seem to apply to any medical tradition. Many aspects of Ayurveda are materialistic. A wide variety of medicinal substances are held to bring about the equilibrium of the components of the body. Observation of physical symptoms (e.g., pain, complexion, strength, appetite, sleep, digestion – Caraka, Vi. 8.89) is central to correct diagnosis and treatment. In addition, the physical environment is held to play an important role in health, disease, and the efficacy of medicinal substances (e.g., Caraka, Vi. 3.7-8). The concept of time also reflects attentive observation of material phenomena (i.e., a broadly empirical stance). For example, time is an important factor in the constitution of the embryo (Caraka, Vi. 8.95, Sa. 2.29). In addition, attentiveness to the seasons and to the temporal progression of diseases is a crucial factor in the administration of therapy (Caraka, Su. 11.46, 13.18-19, 25.45-47, 26.13, Vi. 8.125-128).
Yet, Caraka is explicit that this materialistic dimension is only one approach to medical treatment: [Therapies] are of two types, viz. spiritual and rational. Spiritual therapy comprises incantation, talisman, jewels, auspicious rites, religious sacrifices, oblations, religious rites, vow, atonement, fasting, chanting of auspicious hymns, paying obeisance, pilgrimage, etc. Elimination as well as alleviation therapies and such other regimens, effects of which can be directly perceived, belong to the category of Rational Therapy. Depending upon the nature of their composition, they are also of two types, viz. those having material substrata [e.g., medicinal substances] and those without having any material substrata [e.g., massage, physical restraint, or frightening the patient]. (Caraka Vi. 8.87; cf. Su. 30.28) This sort of reference to religious therapies is exactly the sort of passage that is held to be a later imposition (or earlier survival) by those who argue that Ayurveda is scientific.
Yet merely the presence of materialistic elements does not make Ayurveda scientific. The above list of material phenomena to be observed underlines the centrality of empirical observation in Ayurveda. But, again this is not sufficient to make it science. For example, observation is used to draw non-material conclusions: Caraka holds, for example, that an observable "twinkling of the eye" is evidence for the existence of the Absolute Soul (Sa. 1.70). Caraka goes so far as to label as "heterodox" the view that sensory perception is the only path to valid knowledge, insisting on "other sources of knowledge, viz., scriptural testimony, inference and reasoning"; moreover, Caraka insists that "it is not correct to say that only things which can be directly perceived exist, and others do not" (Su. 11.8). Ayurveda's emphasis on observation as a source of knowledge is not sufficient to support the claim that it was scientific.
To be considered empirical in a scientific sense, a system of thought must do more than simply link knowledge claims to observable phenomena; it must do so in certain ways. To support the strong claim that Ayurveda was science, we would need to demonstrate that ayurvedic knowledge was arrived at or extended through processes of experimental verification or falsification. We would need to ask whether the medical concepts were accepted, modified or rejected on the basis of observation or experimentation. An empirical relation between data and practice is very different from one between data and theory.
There is no evidence of experimentation as a means of verifying/falsifying theories in classical Ayurveda. Zimmerman finds "No examination, no research, no enquiry or attempt to find a reason for the data. .." (1987:158). Of course, the texts do encourage certain sorts of observation. Students of Ayurveda are instructed to learn anatomy from "direct personal observation" of "all the various different organs, external and internal" of a human corpse that has soaked in water for a week (Susruta, Sa. 5.50-56). Practical knowledge is also grounded in direct experience: students are to practice surgical techniques on gourds and dead animals (Susruta, Su. 9.1-3). More intriguingly, the texts give occasional instructions for empirical tests to determine the specific nature of substances: The test in the case of Gangam rain water consists on exposing to it, for [48 minutes], a quantity of undiscoloured Shali rice in a silver bowl. … Gangetic rain water should be ascertained from the fact of the aforesaid Shali rice not being in any way affected in its colour. (Susruta, Su. 45.3) Although such examples reinforce the claim that Ayurveda is empirical in a weak sense, they do not indicate a properly scientific relation between theory and data. Quantification is often considered a key characteristic of scientific reasoning and method as manifested in ancient medical systems (Lloyd 1986:257). The classical Ayurvedic texts show some limited evidence of this, but not enough to qualify as properly scientific. The ayurvedic texts also attend closely to time, with an emphasis on astrological timing, and attentiveness to the seasons, the duration of alterations in diet during periods of therapy, and cycles of human life and reproductive processes. They specify appropriate dosages of medicinal substances. All these factors again underline the importance of observation. These examples, however, do not "go far beyond the range of what could be justified fairly straightforwardly by appeals to readily accessible evidence"; they do not even attempt the "spurious quantification and ad hoc numerological elaboration" that G.E.R. Lloyd finds in some Hippocratic texts (1986:257).
In other words, we find an instantiation of sankhya (enumeration), a notion important in Indian thought, and we find enumeration linked in a very general way with observation; but we do not find the connections between quantification, experimentation, and theory generation that are hallmarks of modem western science. Once again, claims that Ayurveda was, in fact, scientific in this narrow sense are not supported.
A rigorous conception of proof is another criterion of science that is not clearly instantiated in the classical Ayurvedic texts. The path by which ayurvedic knowledge was generated and established is unclear. We can neither credit nor discount a claim that this knowledge was proven empirically.
Despite claims to the contrary, Vedic ritual appears not to have manifested an explicit notion of proof (Lloyd 1990:98- 104). The ayurvedic texts emphasize authority and tradition, rather than proof and empirical evidence, as sources of legitimacy for medical knowledge (Caraka, Vi. 8.13-14). Nor is there any appeal to any conception of proof in the rules for debate between physicians (Caraka, Vi. 8.15-28). Emphasis is placed almost exclusively on the personal qualities of participants. The text sets out normative standards for supporting substantive positions taken by practitioners within the discipline, and issues of proof do not receive even a superficial nod. Argument is rhetorical not empirical. This neglect of empirical evidence supports the view that Ayurveda's empirical characteristics were neither logically nor practically fundamental in a manner analogous to modem science.
It is not surprising that Ayurveda involved different criteria for authority than does modern western science. However, this difference is one more counterargument to claims that it was scientific in this narrow sense.
Two other arguments that Ayurveda was scientific point to its conceptual apparatus. First, a set of four concepts (rasa, vipaka, virya and prabhava) deals with pharmacological anomalies (Caraka, Su. 26.53-79; Sharma 1994:184-187; cf. Susruta, Su. 40). That is, these concepts appear at first sight to represent theory modification in the light of empirical observation. Second, the concept of yukti represents a form of empirically based inference uniquely defined by Caraka (Su. 11.21-25; cf. Dasgupta 1932:376nl). A closer examination of these concepts will show that, although they are clearly empirical in a limited sense, they are not scientific as Chattopadhyaya (1977:7, 9, 175-179, 207, 314ff., 390) and Larson (1987:250-51) suggest. Ayurveda has a well-developed set of logical concepts and categories, reflecting its emphasis on causal analysis. It explains the effects of medicinal substances in terms of putatively material substances and processes using an equilibrium model of health. Ayurvedic theory draws on philosophical concepts from other ancient schools of thought. However, it displays several unique characteristics. The logical examples found in the Caraka are almost entirely of a medical nature, suggesting that they are integral to Ayurveda rather than grafted on (Dasgupta 1932:402). In addition, Caraka mentions but does not use terms for "cause' drawn from different traditions, indicating a reliance on its own tradition of causal analysis (Dasgupta 1932:395). Medicinal substances are categorized at the most general level according to their rasa, taste (Caraka, Su. 26.53-79; cf. Susruta, Su. 40). Substances with specific combinations of rasa are held to act in specific ways upon the dosas. A physician infers a specific imbalance of the dosas from the patient's constitution, symptoms, habitat, and the time of year. He then prescribes a specific diet or medicine that is chosen with regard to its rasa, so as to counteract the imbalance of the dosas. The ayurvedic physicians recognized, however, that some substances did not have the effect they should have, given their rasa. That is, they recognized that their most basic concept of pharmacological categorization did not always reflect empirical facts. This seems a type of trial and error methodology but is not in itself scientific. Where the medicinal action of a substance did not agree with its rasa, the discrepancy was accounted for with the second-level concept of vipaka (post- digestive taste). That is, the action of the substance was still a result of "taste," but of a taste that resulted from changes to the substance in the human body. Caraka and Susruta disagree over the vipaka of certain substances, which suggests that the inference of a substance's vipaka from its medicinal effects was somewhat problematic (Meulenbeld 1987:10).
The physicians recognized further that sometimes substances with the same rasa and the same vipaka still differed in their effects. This was accounted for with the third-level concept of virya (potency). In the case that two substances had the same rasa, vipaka and virya and still differed in their effects, this was accounted for with the fourth-level concept of prabhava (specific action).
This repeated invocation of higher-level concepts to explain anomalies is ad hoc. In its broader sense, the fourth-level concept, prabhava refers to a power, generally seen as inaccessible to reason, which is manifested in the effects of rasa, vipaka and virya. In its narrower sense, prabhava refers to a power, not accessible to reason, that a given substance has by virtue of its svabhava (nature) (Meulenbeld 1987:14). Svabhava, inherent nature, is the reason that each substance has the qualities or properties that it has: each substance is what it is just because it is that way. Chattopadhyaya translates svabhava as "laws of nature" and argues that the concept demonstrates the scientific nature of Ayurveda (Chattopadhyaya 1977:9, 175-179). This is misleading, given that svabhava is a quiddity beyond the reach of reason: the ultimate explanation for the behaviour of specific substances is that it is their nature to behave this way.
Filliozat argues that Ayurveda is not empirical on these very grounds: this chain of concepts is "a dogmatism which interprets experience" not a theory responsible to empirical evidence (Filliozat 1964:30).
The series of concepts, rasa, vipaka, virya and prabhava show that ayurvedic theory recognized pharmacological anomalies but dealt with them, ultimately, by placing them beyond rational explanation. These concepts demonstrate a clear interplay between empirical observation and theory, but one that is stipulative not scientific. When the facts did not fit the theory, the theory was saved by appeal to a concept beyond empirical observation; it was not modified to more accurately reflect the facts.
The fact that observations led ultimately not to theory modification but to an appeal to an irrational concept of nature collapses any analogy with modem science (cf. Meulenbeld 1987:4; Filliozat 1964:29-30).
A separate argument for the scientific status of Ayurveda rests on the epistemological concept of yukti. According to Caraka, there are four means of attaining knowledge: reliable testimony, perception, inference, and yukti (Su. 11.21-25; Wujastyk 2003:25; Sharma 1994:72). Yukti, as a term for "reason," has stood in tension with "authoritative tradition" at several points in the history of Indian thought (Halbfass 1988:207, 278-79, 389, 536n16, 541n94). However, as defined in Caraka, the concept is unique to Ayurveda: "When from a number of events, circumstances, or observations one comes to regard a particular judgement as probable, it is called yukti…" (Dasgupta 1932:376nl). Caraka says little regarding the definition or application of yukti. Yukti "perceives things as outcomes of [a] combination of multiple causative factors" (Su. 11.25). As examples, Caraka mentions forecasting a harvest from the condition of the seed, ground and weather, reasoning that fire will be produced when two pieces of wood are rubbed together with sufficient vigour, and predicting the efficacy of therapeutic measures based on specific symptoms. Chattopadhyaya argues that yukti, which he translates as "rational application," indicates the scientific nature of Ayurveda (1977:7, 207, 314ff., 390). Gerald Larson echoes this claim when he translates yukti as "heuristic reasoning" and claims that "what the medical practitioners are trying to get at with their notion "Science" vs. "Religion" in Classical Ayurveda 429 of yukti [is] an empirical and, indeed, experimental scientific (in the modem sense) approach to reality and experience" (1987:250-51).
Although yukti is another example of an impressive attentiveness to empirical observation, there are problems with the claim that the concept made Ayurveda scientific.
First, the characterization of yukti is too sketchy and ambivalent to support such a claim.
Second, the most important classical medical commentator, Cakrapani, (as well as the non-medical commentator Santaraksita) and the respected historian of Indian philosophy Surendranath Dasgupta, question the status of yukti as a separate means of attaining knowledge: they argue that it is properly subsumed under the more general case of inference (Dasgupta 1932:375). Caraka equates the two at a different point (Vi. 4.4).
Third, even granted the value of such a conception of causal inference within an empirical medical tradition, there is no reason to see this as a properly scientific characteristic. The concept of yukti is another indicator of the medical tradition's attentiveness to empirical data but not an indicator of a scientific relation between these data and medical theory.
In sum, the strong claim that Ayurveda was scientific fails, though the centrality of empirical observation is obvious. Ayurveda simply does not manifest characteristics of modem science in anything more than a vague analogous sense.
To say that ayurvedic physicians were "working scientists" who developed "the scientific method" (Chattopadhyaya 1986:34) or that Ayurveda manifested an "experimental scientific (in the modem sense) approach to reality and experience" (Larson 1987:251) is simply wrong.
This is true whether we consider materialism, empiricism, quantification, experimentation, verification and falsification, or theory modification as characteristics of science and scientific method. The claim that Ayurveda was scientific reduces to the claim that it was broadly empirical.