As mentioned above Ayurveda is a science of life so to know more about it, we must know what is life? Life according to Ayurveda is a combination of senses, mind, body and soul. So it is clear from this definition of life that Ayurveda is not only limited to body or physical symptoms but also gives a comprehensive knowledge about spiritual, mental and social health.

 It is an ancient, unfailing system of treatment based on medicines prepared from herbal plants found in abundance in India. Ayurveda is an integral part of the people of India. This ancient knowledge system of medicine has gained global acceptance especially for alternative ways of preventive, curative and rejuvenate processes making life a more pleasurable experience. This has a holistic approach and it helps maintain the balance of the physiological systems and plays a vital role in preventing diseases and revitalizing the entire life system body, mind and soul.

The basic doctrine on which the Ayurvedic conception of physiology, pathology, pharmacology, medicine and therapeutics are founded is known as the Doctrine of Panchabhutas. This doctrine has been expounded, among others, by the Shad-Darsanas of the sic philosophical systems of India. Of these, Ayurveda has largely relied on the Nyaya-Vaiseshika and Sankhya-Yoga Systems.

It has to be observed that the term philosophy used here should not be confused with religion, as is generally the case. Ordinarily, this term has often been confused with the supernatural and the superstitious. On the other hand, it has been understood and used in the past as in the present, to signify, "the science which aims at the explanation of all phenomena of the universe by ultimate causes," and "as the science which aims at an explanation of all phenomena as explained by and resolved into causes and effects." The term phenomenon used here means, "the form through which, it (the thing) becomes known to the senses or understanding. It is the opposite of the term ‘noumenon,’ which means, "the unknown and unknowable substance or thing as it is in itself." In other words, the former tern is used whenever materialisation and manifestation perceivable by our senses has taken place (i.e.) Vyakta, and the latter term is used whenever things exist in an unmanifested or Avyakta state:

"Whatever is perceptible, being apprehensible by the senses in the manifest or Vyakta, but what is inperceptible and is beyond the senses and can be known only by inference is the unmanifest."

Philosophy can be classified under the following three broad - based headings viz.,

1. The Natural Philosophy - Physics, Chemistry, etc.
2. Mental Philosophy - Meta-physics etc.,
3. Moral Philosophy - Ethics, etc.

In the context of Ayurveda or the Science of Life or Knowledge of Life, the term philosophy comprehends all these three categories which, between them, seek to elucidate and explain the phenomenon of life and life process and lay down the laws and principles that govern them. The Shad-Darsanas claim to have sought for and ascertained the ultimate causes relating to life and life process in terms of causes and effects and enunciate the laws and principles that govern them.

 The term Darsana which is derived from the root ‘Dris,’ means "to see" "seeing," "looking" or "sight." It also means, the ‘eye’ ‘mirror’ and ‘knowledge.’ The Aptas like Kapila, Kanada, Goutama, Brihaspati and the rest who were the authors of the respective Darsanas viz., Sankhya, Vaiseshika, Nyaya and Charvaka Darsanas are, according to Nyaya Sutras, those who taught what they saw. Aptas, say the Sutras, "may be Rishis, Aryas or Melechas."

In order that we may not mix up these philosophical systems with religion, supernatural and superstitious, it may be noted here, that these systems include the materialistic or atheistic philosophy of the Charvakas - the Charvaka Darsanas. The Charvakas, while denying the existence of God or a Creator, held that every aspect of the phenomena of the universe including life, was the result of the combination of the atomic particles. For that matter, the Sankhya system is of two kinds viz., the Seswara Sankhya and Niriswara Sankhya. Whatever the difference between one system and another, all of them are material basis of the phenomenal universe and every thing included in it.

The modern concepts of the physical basis of the universe or matter may be summed up as follows:

 Being with the views propounded by early Greeks - Aristotle, Leucippus, Democritus, Lucretius and the rest, the mechanical principles representing the body of thought enriched later by the contributions of Keeper, Galilee, Newton and others, centred on the concepts of mass, motion and force, became precise in the atomic theory by the end of the 19^th century. According to this theory, every material object could be analysed back and back till we reached the atoms - some 92 elementary substances - which are incapable of further division, or cannot be broken down into something simpler. These elemental particles were conceived as contributing to the constitution of matter. This theory was soon improved upon and it was shown that that atoms, far from being simple, elementary or uncountable, are of complex structure - a structure comparable to the structure of our solar system in miniature, and a permanent sphere, possessing mass and incapable of undergoing any intrinsic change and the following motions which could be determined exactly. These atoms were considered to be the brick-blocks of elementary particles with which all things in the universe are built up. The atomic brick-blocks of matter or chemical atoms were shown to composed of still smaller particles of matter representing packets of electrical energy (quanta), some charged with negative electrical charge, some with positive charge and still a third variety having no charge or neutral, their arrangement and movements in fixed orbits within the atomic space resembling the pattern of our solar system viz., the Sun surrounded at varying distances by its satellites - the Earth, Venus, Moon, Jupiter, Mercury, Neptune, Saturn, etc. These particles are stated to be the bricks which make up the brick-blocks of atoms. So far, about 10 such particles have been described. The more important of these are:

1. The Proton - A heavy particle bearing a positive charge - heavier than electron; posseses one mass unit; forms part of the nucleus of the atom together with another particle-the-Neutron which has no electrical charge. The two together represent the Sun in the atomic Solar system.
2. The Electron - A small light particle with a diameter of about 10-13 centimetre and a mass of about 1/2000 mass units; has a negative electric charge which forms the neutral unit of electricity.
3. The Neutron - A particle possessing a mass unit but no electrical charge and forms the nucleus of the atom together with Protons.
4. Positron - A particle bearing one positive charge, yet possessing a mass much smaller than that of the Proton, known as positive electron.
5. Photon - Unit of radiation.
6. Meson - A charged particle having a mass intermediate between the proton and electron.

(Note: - The diameter of atoms are of the order of 10-8 centimetres (i.e. 100 millionth part of a centimetre). The mass of an atom (absolute) is also very minute and it is simply called atomic mass unit. A mass unit is defined as 1/16 of the mass of an atom of oxygen. The diameter of an electron is about 10-13 of a centimetre and its mass about 1/2000 mass units)

 As in the case of the solar system, so also in the atom, the Nucleus (containing the protons and the neutrons) take the place of the Sun and the electrons represent the planets. They move around the nucleus at different distances from it. Chemical reactions between atoms involve only the outermost electrons. When two atoms combine, an electron may be transferred from one atom to another or they may share two or more electrons. The way in which an atom reacts chemically, therefore, depends on the structure of its electron system. This is determined essentially by the electrical charge on nucleus. The electrons are always in motion around the nucleus in orbits. The centrifugal force created in consequence prevents them from being drawn in by the electric attraction and the atom is thus rendered neutrals.

 This apparently simple picture has become complicated with the discovery of other particles and the possibility of many more being discovered, as well as the existence of a large number of them has not been ruled out. The possibility also of these particles not being elementary in a fundamental sense looms large. In the ultimate analysis, all these atomic particles, whether in the lightest hydrogen atom or the heaviest uranium atom, whatever their nature, disposition and behaviour, may be classified under three main heads, viz.,

1. The positively charged,
2. The negatively charged, and
3. The neutrals.

A further development has modified the concepts referred to above. It bases its conclusions on the behaviour of the atomic particles and presents a picture in which, the particles express themselves in different forms at different times viz., as material particles possessing mass and occupying a measurable space. They undergo transformation and thereby, they change their pattern and show themselves as waves, or particles of different mass occupying different positions in the atomic space. Some of these intra-atomic particles are not really particles at all in the true sense of the term, as they do not appear to be permanent and unchangeable. They are seen to undergo changes. Some of them appear to be far from being simple. The latest trend is to regard them as the ‘components of pattern.’

 In the view of those competent to express an opinion on this subject, "the difficulties felt in pursuing the matter further is because of the analytical method, which is the search into the smaller and smaller structures and it has touched the bottom…. The accuracy of space - time measurement cannot be carried any further; it may well be therefore, that we have reached the limit, to the fine structure of the universe or at least to the limit attainable by present methods. The bottom has perhaps been reached, as it were, with wrong kind of anchor. We cannot grasp the pattern of the ultimate structure of things because, we are using the wrong intellectual instruments, and instead of getting a firm hold or a clear vision of the bottom, we stir up with our dragging anchor a multiplicity of more or less spurious particles."

 In this view, physics is now a finite realm of study - a closed subject - and it will become very important to understand what its laws are. If, as Professor Whyte has stated it is true that the bottom has been reached, then "the true form and laws of that basic structure must bear some relation to everything that happens in the world, not only to the entire world of physics but also to life and mind."

The modern trend in this regard can be stated as follows:-

1. Contemporaneous with the disintegration of the mechanical particle picture, the new conception of spatial patterns and their transformation has steadily grown more definite.
2. The theory of mechanical particles is not the complete explanation of the actual phenomena as well till recently believed, and during the last 30 years have to reinterpreted as part of some comprehensive approach.
3. We must not think of patterns as if they were built out of particles but what has been spoken of till now as particles may better be explained as ‘components of patterns.’ The facts accumulated during the last two and a half decades have shown that there is no doubt about patterns - the exact structural patterns of individual atoms, of chemical molecules, of crystals, fibres and so on. According to this view, this knowledge will not be true knowledge, until all the available knowledge on the subject has been co-ordinated under simple laws. The general laws of development and transformation of patterns are still unknown.
4. This new emphasis on ‘pattern and transformation’ has been extended to other sciences as well. In biology, the development of pattern is unmistakable in the growing embryo. The same applies to psychology also. In visual perception and in the process of thought, the determining factor is normally some regular pattern or configuration, some characteristic arrangement which makes the whole, rather than the isolated elements bearing no relations to one another.
5. The need to restore balance, not by paying less attention to the casual analysis of detailed facts, but paying more attention to certain aspects of phenomena till now neglected, like pattern, tendency and transformation has become emphasised. The crucial problem is to discover the relation of measurement, number and quality on the one hand to some unknown law that governs the development and transformation of pattern on the other.
6. The difficulty inherent in the problem is not overlooked and it in recognised that all measurement rest on the conception of some unchanging permanence, either of a scale or a clock, while transformation involves process or change. Hence it is recognised that the task of physics is to discover a new principle which can unite permanence to change - a new kind of causality to prove a broader and more reliable foundation.
7. These trends have led to the development of a "New-outlook" in the physicists, who till recently believed that they could formulate the laws of physics without any reference to the investigator, the scientists and others who are interested in these laws and make the observations. As observed by Mott, "the scientist to-day does not feel any more that he is investigating some absolute truth, remote from mankind and this too is probable why he feels that the subject matter of his science physics, is the relation between mankind and the rest of the world."

 The pursuit of the knowledge of matter, or ‘Padartha-Vignana’ has, we have seen, taken the scientist from the realms of the seen or sense perception, to the realms of the unseen and intellectual abstractions. This has raised an interesting but to us a familiar discussion on the "Seer and the Seen" or the "Subject and the Object." Einstein, Bohr and Born and a host of the front rank scientists of the world to-day belong to a school which taught that, "There exists an objective world which unfolds itself according to immutable laws independent of us; we are watching the process as the audience watches a play in a theatre." Of these scientists, some subscribe to the view similar to the Advaitic that, "there is no objectively existing external world, no sharp distinction between the subject and object," and following on Henri Poincare, some among them hold that, "all human concepts are free inventions of the mind and conventions of various minds; they are justifiable only by their usefulness in ordinary experiences."

 The Ancient Indian Concepts - the Arambha Vada and Parinama Vada

 It was stated elsewhere that Ayurveda has mostly relied on the Nyaya - Vaiseshika and Sankhya - Yoga systems of natural philosophy. These systems represent conclusions and generalisations - axiomatic truths - that occur in the form of sutras which are terse and aphoristic in style. It is seen from a close examination of these conclusions that their approach to the phenomenon of the universe is generally ‘synoptic’ or ‘wholistic’ in nature and they look at the ‘part’ in terms of the ‘whole,’ or, in the context of the whole. In other words, the idea that the whole permeates its parts become emphasised.

 It is perhaps necessary for us in this connection to familiarise ourselves with the ancient views on the manifestation of the universe viz., the Arambha Vada and Parinama Vada. The former concept posits that the order of creation was primarily in the nature of creation first of the paramanus or atoms of Vayu, Thejas, Ap and Prithvi, and the things in the universe arise by the putting together of two or more atoms of these elemental substances. This school of thought is represented by the Vaiseshikas who believed in a manifold of ultimate ‘Reals’ whose atom combine variously to from the things of the universe.

 The latter, Parinama Vada, postulates that all things including what are spoken as ‘Reals’ arise out of an evolutionary transformation within the primary ground substance. This view provides for a quantitative permanence and transformation; in fact it relates the latter to the former and is represented by the Sankhya system.

 These two schools, it will be seen, seek to explain the same phenomenon in two ways. The former reduces all physical phenomena to an irreducible final state designated as the ‘Tatwas’ or ‘Reals,’ which by combining and recombining form the phenomenal universe and every thing included in it. The position taken by them will become intelligible to all who are acquainted with the stand taken by physicists some 50 years ago, with this difference that the 92 chemical atoms represented to them the ultimate ‘Reals’ or ‘Tatwas,’ which by combining variously, were stated to have resulted in all the things that make the universe.

 The latter school of thought, on the other hand, has taken a position similar to that of the more advanced physicists of to-day that, in the ultimate analysis, the matter that constitutes the physical universe is, (i) component of patterns, (ii) it interprets pattern, tendency and transformation, (iii) it has stated the laws governing the development and transformation of patterns, and (iv) also the law or principle which unites permanence to change. Stated in brief, the Parinama Vada, representing the Sankhya school of natural philosophy have, while nothing the existence of what the Vaiseshikas designate as the ‘Reals’ or ‘Tatwas’, held that the so-called ‘Reals’ are nothing, if not, stages in the evolutionary transformation of the one permanent substance. They laid down the law that governs the development and transformation of patterns and enunciated the principle which unites changes to permanence. The first substance out of which is multiplicity of heterogeneous substances in their infinite diversity have evolved by evolutionary transformation, was designated by the term ‘Mula Prakriti’ or the Root or Primordial matter.

 This system which occupies a pre-eminent position on the history or philosophical thought in India has given an explanation of our experience; has presented a comprehensive picture of the process of cosmic evolution, viewed not merely as a pure metaphysical speculation but as a positive principle based on the conservation, transformation and dissipation of energy.

The science of Ayurveda is primarily concerned with life, life process and living states. Its approach to all phenomena is with reference to and from the point of view of living beings. In his approach to this environment, the subject employs the instrumentality of his mind, and senses which are five in number. The former is known as the Anthahkarana or the inner instrument, and the latter as Indriyas, the external instruments through which the former, under ordinary circumstances, views the universe. It is the samyoga or correlation of the mid with the objects of its interest through the senses that completes the process of perception. This view, which is an ancient one has endured the test of time and is being restated to-day by modern science. Says P. Ouspensky, the leading mathematician philosopher of Russia, "Cognition of space and time (it may be noted here that Kala and Dik or time and space, are considered as Dravyas or substances by the Vaiseshikas), arise in our intellect, during its touch with external world by means of the organs of sense and do not exist in the external world apart from our contact with it."

 This would bring us to the consideration of Charaka’s conception of; a (a) Phenomenon and Noumenon; (b) Universe and the Man; (c) Life or Ayus; (d) the Tripod that constitutes Man; (e) the Subject or Purusha; (f) Mind of Manas - it structure and function; (g) Objects of these senses; (h) the correlation of the Subject with the Object, and (i) the limitations of sense-perception.

1. Phenomenon or Vyakta: "Whatever is perceptible being apprehensible by the senses is the manifest or Vyakta."

Noumenon or Avyakta: "What is perceptible and yet is beyond the senses and can be known only by interference - the unmanifest - is Avyakta.

2. The Universe and the Man: "Man is the epitome of the universe. There is in him as much diversity as in the universe outside him and there is in the universe as much diversity as in man."
3. Life of Ayus: "The life is spoken of by such synonyms as the union of body, the senses, the mind and spirit; the support, animation, the flux, and the line (between the past and the future)."
4. The Tripod that constitutes Man: "The Mind, the Atma and the Body together as it were, are the Tripod; the universe endures by reason of cohesion and all things are established therein."
5. "The Subject or Man is stated to the sum of six elements viz., the Akasa and the four elemental substances, the sixth being the element of consciousness. Some hold that the element of consciousness alone constitutes Man."

"Again as a consequence of the elemental modifications man is said to be composed of twenty-four elements viz.,

the mind, the ten organs (the five Jnana or cognitive and five conative)."

6. Manas or Mind: "The presence of cognition as well as the absence of cognition constitutes the indication of mind. Thus, if Atma (Spirit), the senses and the sense-objects are opposite and the mine is elsewhere, there is no cognition. But with the mind present, there is cognition. The mind is stated to have two properties - atomic dimension and an indivisible unity."

The functions of the Mind: "The functions of the Mind are the direction of the senses, control of itself,

reasoning and deliberation. Beyond this is the field of the intellect."

7. The Artha or objects of the senses: "Whatever admits of being thought about, considered, speculated, meditated upon, imagined, in fact whatever can be known by the mind, all goes by the name objects."
8. Methods of correlation of the Subject with the Object: "The sense object is cognised the sense which is in contact with the mind. Thereafter, the object is interpreted or understood the mind with reference to its merits and demerits. Guided by whatever conclusive judgement thus formed regarding the matter in hand, one endeavours to speak or act, fully aware of the nature of one’s action."

 The Visible & the Invisible: (i) "The visible is limited, while there exists a vast unlimited world of which we are made aware by the evidence of authoritative Agamas, inference and reason. In fact, even the very senses by whose agency direct observations are obtained are themselves outside the range of observation."

 The limitation of perception: "Further, even perceivable objects escapes observation under the following conditions:-

 When it is either too close or too distant from the observer; when it is obstructed by other objects; when there is some defect in the perceiving sense-organ, when the observer’s attention is focused elsewhere; when the object is merged in the mass; when it is overshadowed by some thing else or lastly when it is microscopic."

 In the context of more recent trends in physical biological and psychological sciences, the views of Charaka extracted above assume considerable importance. In certain aspects, the former appears to generally confirm the latter, particularly where it seeks to relate the object to the subject to complete the process of perception and the role of the mind in the fruition of this process. The fact that the physical world is the world of the senses, the sense data are the foundations of physics: and so the physical world is the world reported to the human mind by the senses and inferred from the data contacted by the senses, and the fact that beyond these lie an invisible and imperceptible state of things which cannot be contacted by the mind through the senses has been affirmed. The following points have also likewise been affirmed:

1. The five senses are so constructed as to enable them to function within fixed and well defined ranges. This would apply to our perception of light which is the object of the eyes, as to sound which is the object of the ear and the same applies to smell, taste and touch also.
2. Ranges above and below to what are normal to these sense-organs are beyond the purview of sense-perception or cognition. Even the employment of external-aids to extend the range of the senses - both ways - does not take us very fat.
3. Senses, either by themselves or supplemented with external aids can, at best, connect the Object to the Subject and they are not the interpreters of the objective phenomena.
4. It is the mind, in the final analysis, which has to work on the data presented to it by the senses, and from out of them reconstruct the phenomenon.
5. The phenomenon thus reconstructed cannot but be incomplete and defective.
6. The nervous system in its different aspects through which the mind operates is designated as the "near-mind."
7. The mind itself, according to modern psychology, is of an imponderable structure. In the view of one school of psychologists, it is compared to an ice-berg with 6/7 of it submerged in the unconscious, and the remaining 1/7 functioning as the conscious part. The 1/7 part of the mind corresponds to the conscious. It functions actively in wakeful states, when it operates through the senses and contacts environment. Its relations to such contacts are governed by the laws of Time and Space. As such, the knowledge gained by the mind under such conditions cannot but be limited.
8. It has been noted by modern workers that the mind frees itself from its association with the senses in certain special states, when it is stated to be above considerations of time and space. According to the psycho-analyst Dr. Godwin Baynes, "The unconscious is merely a term which comprises every thing which exists, that has existed or that could exist beyond the range of this individual consciousness." Another modern authority, William James, referring to an examination he had made of nitrous-oxide intoxication says, "one conclusion was forced upon my mind (at that time) and my impression of its truth has ever since remained unshaken. It is that our normal waking consciousness, rational consciousness as we call it, is but one special type of consciousness, whilst all about it, parted by it by flimsiest of screens, there lie potential forms of consciousness entirely different. We may go through life without suspecting their existence; but, apply the requisite stimulus, and at a touch, they are there, in all their complete-stimulus, definite types of mentality which probably somewhere have their field of application. No account of the universe in its totality can be final which leaves the other forms of consciousness quite disregarded; yet, I repeat once more, the existence of mystical states absolutely overthrows the pretension of non-mystical states to be the sole and ultimate dictators of what we may believe."