A History of Indian Philosophy Volume 2

by Surendranath Dasgupta | 1932 | 241,887 words | ISBN-13: 9788120804081

This page describes the philosophy of did logic originate in the discussions of ayurveda physicians: a concept having historical value dating from ancient India. This is the fourteenth part in the series called the “speculations in the medical schools”, originally composed by Surendranath Dasgupta in the early 20th century.

Part 14 - Did Logic Originate in the Discussions of Āyurveda Physicians

Dr Mahāmahopādhyāya Satish Chandra Vidyabhusan in his History of Indian Logic supposes without adducing any reason that the Caraka-saṃhitā gives a summary of the principal doctrines of Ānvīkṣikī, possibly as propounded by Medhātithi Gautama. He further says that the doctrines of Ānvīkṣikī evidently did not constitute a part of the original Āyurveda of Punarvasu Atreya, and that these doctrines seem to have been incorporated into the Caraka-saṃhitā by the redactor Caraka, in whose time they were widely known and studied. Dr Vidyabhusan’s theory is that both Caraka and Akṣapāda borrowed the Nyāya doctrines from Medhā-tithi Gautama, but, while Caraka accepted them in their crude forms, Akṣapāda pruned them thoroughly before they were assimilated in the Nyāya-sūtra[1].

But Dr Vidyabhusan’s Medhātithi Gautama is more or less a mythical person, and there is no proof that he ever wrote anything, or that Caraka borrowed anything from a Medhātithi Gautama, or that the Nyāya doctrines found in the Caraka-saṃhitā were not contained in the original treatise of Agniveśa, now lost. Dr Vidya-bhusan refers to the evidence of a number of works, such as the Kusumāñjali, Naiṣadha-carita and Nyāya-sūtra-vṛtti , which refer to Gautama as being the founder of Anvīkṣikī. But none of these authorities are earlier than the tenth century. He refers also to the authority of the Padma-purāṇa, Skanda-purāṇa and Gandharva-tantra, none of which can be regarded as a work of any considerable antiquity.

Vātsyāyana himself refers to Akṣapāda as the person to whom Nyāya (the science of Logic) revealed itself[2]. Uddyotakara also refers to Akṣapāda as the utterer of the Nyāya-śāstra, and so also does Vācaspati[3]. There is therefore absolutely no reason why the original authorship of Nyāya should be attributed to a Gautama, as against Akṣapāda, on evidence which cannot be traced to any period earlier than the tenth century and which is collected from Purāṇa sources directly contradicted by the earliest Nyāya authorities.

The Nyāya-śāstra, therefore, cannot be traced on the evidence of the earliest Nyāya authorities to any earlier Gautama; for, had this been so, it would certainly have been mentioned by either Vātsyāyana, Uddyotakara or Vācaspati. Jayanta also attributes the elaborate Nyāya work to Akṣapāda and does not seem to know that this elaborate treatise, the Nyāya-sūtra , was based on the teachings of an earlier authority[4]. If any such authorities were known, they would certainly have been mentioned for the dignity and the prestige of the Śāstra.

Gautama is an old name, and we find it attached to one of the Rṣis of the Ṛg-Veda (i. 62. 78. 85; iv. 4);

he is mentioned

but nowhere is he spoken of as being the author of the Nyāya-śāstra.

Gautama is also mentioned in the Mahā-bhārata several times, but nowhere is he referred to as the author of the Nyāya-śāstra. The passage of the Mahā-bhārata on which Dr Vidyabhusan bases his theory of a Medhātithi Gautama does not say that Medhātithi was the author of Anvīkṣikī or Nyāya, nor does it say that Medhātithi and Gautama were identical persons[5].

The name Gautama is a patronymic, and the passage of the Mahā-bhārata referred to by Dr Vidyabhusan clearly means that the highly wise Medhātithi of the Gautama race was engaged in asceticism. This is corroborated by the fact that the passage of Bhāsa referred to by Dr Vidyabhusan mentions Medhātithi as a teacher of Nyāya-śāstra and does not call him Gautama, nor does it say that Medhātithi was the originator of Nyāya[6]. Dr Vidyabhusan’s theory, therefore, of Medhātithi Gautama being the originator of the Nyāya-śāstra falls down like a house of cards. His identification of Medhātithi Gautama’s birthplace as Mithilā, his ascertainment of his date, his identification of Persian references to Medhātithi Gautama and his so-styled references to Medhātithi Gautama in the Aṅguttara-nikāya and the Brahma-jāla-sutta are no less fictitious[7]. The Gautama tradition of Nyāya need not be followed; but it may incidentally be mentioned that an Ātreya Gautama, who is described as being Sāṃkhya (probably in the sense of wise, philosopher, or learned), is counted in the list of the sages who assembled together to discover the causes and remedies of diseases; side by side with this Atreya, another Atreya is also mentioned as bhikṣu Ātreya[8].

A number of sages are mentioned in the Caraka-saṃhitā as persons who discussed the problem of the rise of diseases and how they could be removed. Among these Bharadvāja volunteered to proceed to Indra to learn from him the science of healing. Indra instructed him in the subject, being learned in the three subjects of the (hetu) causes (of diseases), knowledge of the (liṅga) signs (of diseases) and the knowledge of medicines. Bharadvāja, having learnt this elaborate science in three divisions, repeated it to the sages in exactly the same manner in which he learnt it. After this it is said that Punarvasu taught Āyurveda to his six disciples, Agniveśa, Bhela and others. Cakrapāṇi, the commentator, says that Punarvasu was the disciple of Bharadvāja, and quotes as his authority a statement of Hārīta. But on this point Caraka himself is silent.

But one thing emerges from this half-mythical account of the origin of Āyurveda, viz. that the Āyurveda was occupied from the beginning with the investigation of the nature of causes (hetu) and reasons (liṅga) for legitimate inferences in connection with the enquiry into the causes of diseases and the apprehension of signs or indications of the same.

In the Nidāna-sthāna of Caraka eight synonyms for reason (hetu) are given, viz.

  1. hetu,
  2. nimitta,
  3. āyatana,
  4. kartṛ,
  5. kāraṇa,
  6. pratyaya,
  7. samutthāna
  8. and nidāna.

It is curious enough that the words pratyaya and āyatana are used, which are presumably Buddhistic. The word pratyaya, in the sense of cause, is hardly found in Indian philosophy, except in Buddhism. The use of so many terms to denote cause evidently suggests that before Caraka’s redaction there must have been an extensive literature which had used these words to denote cause. As a matter of fact, the word pratyaya is hardly ever used in the Caraka-saṃhitā to signify cause, though it is counted here as one of the synonyms of hetu, or cause. The natural implication of this is that the word pratyaya was used for hetu in some earlier literature, from which Caraka collected it; so with other words, such as samutthāna, āyatana, which are counted in the list as synonyms for hetu, but are not actually used in the body of the text. This may lead us to think that the discussion of hetu under various names is an old subject in Āyurveda literature existing before Caraka, from which Caraka collected them.

We know that Āyurveda was primarily concerned with three questions, viz. how diseases originated, how they were known, and what were their cures. It was in this connection that the principle of causality was first from a practical necessity applied in Āyurveda. Thus, if it is known that a person has been exposed to sudden cold or has enjoyed a heavy feast, then, since it is known that cold leads to fever and over-feeding to indigestion, with the very first symptoms of uneasiness one may at once infer that the patient is likely to get fever or to have diarrhoea or acute indigestion. Or, if it is known that the patient has a strong diarrhoea, then it can similarly be inferred that he has eaten indigestible articles. Thus the two principal kinds of inference which were of practical use to the Āyurveda physicians were inference of the occurrence of a disease from a knowledge of the presence of the causes of that disease, i.e. from cause to effect, and inference of the specific kinds of unhygienic irregularity from the specific kind of disease of the patient, i.e. from the effect to the cause. The other and third kind of inference is that of inference of disease from its early prognostications (pūrva-rūpa).

Cakrapāṇi, in commenting on the possibility of inference of specific diseases from their early specific prognostications, compares it with inference of rain from an assemblage of dark clouds or of the future rise of the Krttika constellation from the rise of the constellation Rohiṇī, which immediately precedes it. Both these are cases of inference of future occurrences of causation or coexistence. The prognostication may, however, be of the nature of an immediately and invariably associated antecedent which may drop altogether when the disease shows itself. Thus before a high fever the hair of the patient may stand erect; this standing erect of the hair in a specific manner is neither the cause nor is it coexistent with fever, since it may vanish when the fever has actually come. It is, however, so invariably associated with a specific kind of fever that the fever can be inferred from it[9].

Again, when there is any doubt among a number of causes as to which may be the real cause of the disease, the physician has to employ the method of difference or the method of concomitant variation for its proper ascertainment. That similar things produce the same kind of effects and opposite things produce opposite results are two of the accepted postulates of the law of sāmānya and viśeṣa in the Caraka-saṃhitā[10]. Now, applying these two principles, it is held that in a case of doubt as to any kind of irregularity being the cause of any particular disease it has to be found out by experiment whether the application of the suspected cause (e.g. cold) increases the disease (e.g. fever); if it does, and if the application of its opposite (e.g. heat) decreases the disease, then cold is to be regarded as the cause of the disease. If the application of any particular kind of element increases an effect (a particular kind of disease) and the application of its opposite decreases it, then that particular element may be regarded as the cause of that effect.

Caraka holds that the three methods, viz. the cause and effect relation (nidāna), the method of invariable prognostication (pūrva-rūpa) and the method of concomitant variation (upaśaya, which includes anupaśaya also) are to be employed either jointly or separately for the ascertainment of the nature of diseases which have already occurred or which are going to happen in the near future[11]. Caraka thus urges that the physician should examine carefully the causes of diseases by the application of all these methods, so that they may be ascertained from their visible effects. Caraka then goes on to give examples of a number of diseases and the causes or prognostications by which their nature can be ascertained. He then says that a disease which is at first only an effect of some other causes may act as a cause of other diseases and may thus be regarded both as an effect and as a cause. There is therefore no absolute difference between a cause and an effect, and that which is a cause may be an effect and that which is an effect may also in its turn be a cause.

Sometimes a disease may behave as cause of another disease and then cease to exist itself, whereas again, one disease may exist side by side with another disease which it has produced and aggravate its effects. Then, again, a disease (cause) may produce a disease (effect), and that effect another effect. Thus one cause may produce one effect as well as many effects, and one effect may be due to one or to many causes, and again many causes may jointly produce many effects. Thus, though fever, delirium, etc. may all be produced by dryness (rūkṣa), yet under certain circumstances fever alone may be produced by it. Again, fever may also be produced by the combination of a number of causes which under other circumstances may produce jointly a number of diseases. So one entity may be an invariable concomitant (liṅga) of one event or of many events, and there may also be a number of invariable concomitants of one event. Thus fever is the invariable concomitant of hygienic irregularities in general, and all fevers have heat as their invariable concomitant. From certain kinds of hygienic irregularities fever can be inferred; but these can also be associated with a number of other diseases[12].

Hence it is evident that the determination of the nature of causes and effects and the inference of facts or events of invariable concomitance were an indispensable necessity for the Āyurveda physicians in connection with the diagnosis of diseases and the ascertainment of their causes and cures. It was for this reason that Caraka divided inference into three classes, from causes to effects, from effects to causes and from the association of other kinds of invariable concomitants.

The Nyāya-sūtra of Akṣapāda contains expressions which seem to have been borrowed from Nāgārjuna’s Mādhyamika-kārikā and from the Laṅkāvatārasūtra and the regulations of Buddhistic idealism, and hence it is generally believed to have been composed in the second or the third century A.D .[13] In this fundamental and earliest work of Nyāya philosophy inference (anumāna) is described as being of three kinds, viz. from cause to effect (pūrvavat), from effect to cause (śeṣavat), and inference from similarities (sāmānyato-dṛṣṭa) not comprehended under the cause-effect relation. Now it is exactly these three forms of inference that are described in the Caraka-saṃhitā, and, so far as is known to the present writer, this is the earliest work which describes inference in such a systematic manner, and so it may naturally be regarded as the source from which Akṣapāda drew his ideas. Now Caraka’s work may be regarded as a revision of Agniveśa’s work, based on Atri’s teachings, based on Bhara-dvāja’s instructions.

Agniveśa’s work is now lost, and it is not known what exactly were the contributions of Caraka in his revision of Agniveśa’s work; but, since we find no work of an earlier date, Hindu, Buddhist or Jaina, which treats of the logical subjects found in the Caraka-saṃhitā, and since these logical discussions seem to be inextricably connected with medical discussions of diagnosis of diseases and the ascertainment of their causes, it seems very natural to suppose that Caraka got his materials from Agniveśa, who probably got them from still earlier sources. Incidentally it may be mentioned that Jayanta, in his Nyāyamañjarī, discussing the question of the probable sources from which Akṣapāda drew his materials, suggests that he probably elaborated his work from what he may have gathered from some other science (śāstrāntarābhyāsāt); but it is difficult to say whether by śāstrāntara Jayanta meant Āyurveda. The Nyāya-sūtra, however, expressly justifies the validity of the Vedas on the analogy of the validity of Āyurveda, which is a part of the Vedas[14].

The similarity of the Nyāya-sūtra definition of inference to Caraka’s definition is also very evident; for while the former begins tat-pūrvakaṃ tri-vidham (where tat-pūrvakaṃ means pratyakṣa-pūrvakaṃ), the latter begins pratyakṣa-pūrvakaṃ tri-mdham tri-kālaṃ. But, while Caraka knows only the three forms of inference, he has no names for these three types such as are supplied by Akṣapāda, viz. pūrvavat (related to pūrva, the prior, or the cause), śeṣavat (related to śeṣa, the later, or the effect) and sāmānyato-dṛṣṭa (from observed similarity in the past, present and future, which is also emphasized by Caraka in the same manner)[15]. From the considerations detailed in the preceding footnote it may well be assumed that Akṣapāda’s contribution to the definition of inference consists in his giving names to the types of floating inference described in Caraka-saṃhitā. It is not improbable that the Nyāya-sūtra derived its theory of five propositions, and in fact most of the other logical doctrines, from Caraka, as there are no earlier works to which these can be traced[16].

Caraka’s definition of perception as the knowledge that arises through the contact of the self, the senses, the mind and the objects seems very much like an earlier model for Akṣa-pāda’s definition of perception, which adds three more qualifications to make the meaning more complex and precise[17]. The idea that in the first instance perception is indeterminate (nir-vikalpa or a-vyapadeśya) is a later development and can hardly be traced in Hindu philosophy earlier than the Nyāya-sūtra [18].

The similarity of the various categories of

as enumerated in Caraka, to those of the Nyāya-sūtra has been duly pointed out in a preceding section. The only difference between the two sets of enumeration and their elaboration is that Caraka’s treatment, being the earlier one, is less full and less complex than that of Akṣapāda.

The fact that physicians in counsel earnestly discussed together, in order to arrive at right conclusions regarding both the theoretical causes of diseases and their cures and their actual practical discernment in individual cases, is abundantly clear from even a very superficial study of the Caraka-saṃhitā. The entire work seems to be a collection of discussions of learned physicians with Atri as their chairman. Where differences of opinion are great, they are all noted, and Atri’s own opinion on them is given, and, where there was more or less unanimity, or where Atri himself lectured on specific problems, his own opinion alone is given. It is also related how a good and clever physician is to defeat his opponents in dispute, not only in a legitimate and scientific way, but also by sophistic wrangling and unfair logical tricks. It was a practical necessity for these physicians to earn their bread in the face of strong competition, and it is easy to see how the logical tricks of chala, jāti and nigraha-sthōna developed into a regular art of debate, not always for the discovery of truth, but also for gaining the victory over opponents.

We hear of debates, discussions or logical disputes in literature much earlier than the Caraka-saṃhitā', but nowhere was the acquirement of this art deemed so much a practical necessity for earning a living as among the medical men. And, since there is no mention of the development of this in any other earlier literature, it is reasonable to suppose that the art of debate and its other accessories developed from early times in the traditional medical schools, whence they are found collected in Caraka’s work. The origin of the logical art of debate in the schools of Āyurveda is so natural, and the illustrations of the modes of dispute and the categories of the art of debate are so often taken from the medical field, that one has little reason to suspect that the logical portions of the Caraka-saṃhitā were collected by Caraka from non-medical literature and grafted into his work.

Footnotes and references:


History of Indian Logic, pp. 25 and 26, by Mahāmahopādhyāya Satish Chandra Vidyabhusan. Calcutta University, 1921.


Yo ’kṣapādam ṛṣiṃ nyāyaḥ pratyabḥād vadatāṃ varam
tasya Vātsyāyana idaṃ bhāṣya-jātam avartayat.
, 2. 24, A.D. 400.

Dr Vidyabhusan’s translation of it as “The Nyāya philosophy manifested itself (in a regular form) before Ak§apāda” is inexact.


yad Akṣapādah pravaro munīnāṃ
śamāya śāstram jagato jagāda.

      Nyāya-vārttika of Uddyotakara (a.d. 600).

Opening lines. atha bhagavatā Akṣapādena niḥśreyasa-hetau śāstre praṇīte. Nyāya-vārttika-tāt-parya-pkā of Vācaspati. Dr Vidyabhusan’s translation of the Nyāya-vārttika word śāstra as “Nyāyaśāstra in a systematic way” is again inexact.


Akṣapāda-praṇīto hi vitato Nyāya-pādapaḥ.

Opening lines of the Nyāya-mañjañ of Jayantabhafta (a.D. 880).


Medhātithir mahā-prājño Gautamas tapasi sthitaḥ vimṛśya tena kālena patnyāḥ saṃsthyā-vyatikramam.
      Mahā-bhārata, Śānti-parva,
265.45, Vangavasi edition.


Medhātither Nyāya-śōstram (having learnt Nyāya-śāstra from Medhātithi). Bhāsa’s Pratimā-nāṭaka, Act v, p. 79. M. M. Ganapati Sastri’s edition.


History of Indian Logic, by Dr Satish Chandra Vidyabhusan, pp. 17-21.


Ātreyo Gautamaḥ sāṃkhyaḥ. In this passage Ātreya may, however, be taken as a man separate from the wise Gautama.


These two kiṇḍs of pūrva-rūpa are thus described by Cakrapāṇi in his commentary on Caraka-saṃḥitā, 11. 1. 7:

tac ca pūrva-rūpaṃ ḍvi-vidḥam ekarn bhāvi-vyādhy-avyakta-liṅgam .. .dvitlyaṃ tu doṣa-dūṣya - santmūrchanā-janyam avyakta-liṅgād anyad eva yathā jvare bāla-pradveṣa-roma-harṣādi.


Caraka-saṃhitā, I. I. 44.


The other two methods of saṃprāpti and rūpa need not be discussed in this connection.


See Caraka-saṃhitā, II. 8. 22-27.


H. Ui’s The Vaiśeṣika Philosophy, p. 16.
L. Suali’s Filosofia Indiana, p. 14.
Jacobi, article in J.A.O. Society, vol. xxxi, p. 29, 1911.

A commentary on Nāgārjuna’s Pramāṇa-vidhvaṃsana called Pramāṇa-vidhvaṃsana-sambhāṣita-vṛtti reproduces Nāgārjuna’s definition of the categories, which are the same as the categories enumerated in the first sūtra of Aksapāda’s Nyāya-sūtra. But, as Walleser points out in his Life of Nāgārjuna from Tibetan and Chinese Sources, it is impossible to fix Nāgārjuna’s date exactly. He may have lived at any time between the second and the fourth centuries A.D. So no fruitful result can be attained by considerations of this kind.


Mantrāyurveda-prāmāṇyavac ca tat-prāmāṇyam āpta-prāmāṇyāt.
u. i. 68.

Jayanta enters into a long discussion in his Nyāya-mañjarī, trying to prove that it was through his omniscience that Caraka could write his work and that he neither discovered the science by inductive methods nor derived it from previous traditional sources.


Evaṃ vyavasyanty atītaṃ bījāt phalam anāgataṃ
dṛṣṭvā bījāt phalaṃ jātam ihaiva sadṛśaṃ budḥāḥ.
I. 11. 22.

Vātsyāyana, in his commentary on the Nyāya-sūtra, illustrates pūrvavat (from cause to effect) as the inference of rain from the rise of clouds, śeṣavat (from effect to cause) as the inference of rain in the uplands from the flooding of the river in the lower regions and sāmānyato-drṣṭa (from similar behaviour) as the inference of the motion of heavenly bodies from their changes of position in the sky at different times. But he also gives another meaning of these three terms pūrvavat, śeṣavat and sāmānyato-dṛṣṭa.

He interprets pūrvavat here as the inference of fire from smoke “on the analogy of past behaviour of co-presence,” śeṣavat as the inference of the fact that sound is quality because it is neither substance nor action, by the method of residues (śeṣa), and sāmānyato-dṛṣṭa as the inference of the existence of soul from the existence of desire, which is a quality and as such requires a substance in which it would inhere. This is not an inference from similarity of behaviour, but from the similarity of one thing to another (e.g. that of desire to other qualities), to extend the associations of the latter (inherence in a substance) to the former (desire), i.e. the inference that desire must also inhere in a substance.

In the case of the terms pūrvavat and śeṣavat, as these two terms could be grammatically interpreted in two different ways (with matup suffix in the sense of possession and vati suffix in the sense of similarity of behaviour), and as the words pūrva and śeṣa may also be used in two different ways, Vātsyāyana interprets them in two different ways and tries to show that in both these senses they can be justified as modes of inference. It seems obvious that the names pūrvavat, śeṣavat and sāmānyato-dṛṣṭa were given for the first time to the threefold inference described by Caraka, as this explains the difficulty felt by Vātsyāyana in giving a definite meaning to these terms, as they had no currency either in traditional or in the contemporaneous literature of Vātsyāyana. Uddyotakara, in his commentary on Vātsyāyana, contributes entirely original views on the subject.

He takes Aksapāda’s sūtra,

atha tat-pūrvakaṃ tri-vidham anumānam pūrvavac cheṣavat sāmānyato-dṛṣṭaṃ ca,

and splits it up into

atha tat-pūrvakaṃ tri-vidham anumānaṃ and pūrvavac cheṣavat sāmānyato-dṛṣṭaṃ ca ;

by the first tri-vidha he means inference from positive instances (anvayi), from negative instances (vyatireki) and from both together (anvaya-vyatireki).

He gives two possible interpretations of the terms pūrvavat, śeṣavat and sāmānyato-dṛṣṭa, one of which is that pūrvavat means argument from cause to effect, śeṣavat that from effect to cause and sāmānyato-dṛṣṭa is the inference on the basis of relations other than causal. The Sāṃkhya-kārikā also mentions these kinds of inference.

The Māṭhara-vṛtti again interprets the threefold character of inferences (tri-vidha anumāna) in two ways; it says, firstly, that tri-vidha means that an inference has three propositions, and, secondly, that it is of three kinds, viz. pūrvavat (from the effect, e.g. flooding of the river, to the inference of the cause, e.g. showers in the upper region), śeṣavat (from part to whole, e.g. tasting a drop of sea-water to be saline, one infers that the whole sea is saline), and sāmānyato-dṛṣṭa (inference from general association, e.g. by seeing flowering mangoes in one place one infers that mangoes may have flourished in other places as well).

Curiously enough, the Māṭhara-vṛtti gives another example of sāmānyato-dṛṣṭa which is very different from the examples of sāmānyato-dṛṣṭa hitherto considered. Thus it says that, when one says, “It is illuminated outside,” another replies, “The moon must have risen.”


For more or less fanciful reasons Mr Dhruva suggests that the terms pūrvavat and śeṣavat were borrowed in the Nyāya-sūtra from the Mīmāṃsā-sūtra and that this sūtra must therefore be very old (Proceedings and Transactions of the First Oriental Conference, Poona, 1922). This argument is invalid for more than one reason. Firstly, granting that the Mīmāṃsā-sūtra is very old (which is doubtful), the fact that these two logical terms were borrowed from it does not show that it must be a very old work; for even a modern work may borrow its terminology from an older treatise. Secondly, the fact that these three terms were borrowed from early sources does not show that the theory of tri-vidha anumāna in the Nyāya-sūtra is either its own contribution or very old. Mr Dhruva’s arguments as to the Māṭhara-vṛtti being subsequent to Vātsyāyana’s commentary are also very weak and do not stand criticism.


indriyārtha-sannikarṣotparmamjñānam avyapadeśyam avyabhicāri vyavasā-yātmakāṃ pratyakṣam.
1. 1.4.


Caraka uses the word vikalpa in 11. 1. 10. 4 in the sense of distinction (bheda) of superiority and inferiority (utkarṣa-prakarṣa-rūpa).

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