THE NATURE OF MATTER
Nature and Function of Matter
E. C. G. Sudarshan
Science is the discipline which organizes our experimental communicable ‘public’ knowledge. It is rooted in experience (‘experiment’) and draws on all our linguistic and computational expertise and is thus both a branch of philosophy (‘natural philosophy’) and of semiotics: compare with a page of a research paper in theoretical physics! Depending upon the aspects of experience that are emphasized the kind of science is also altered. If we are dealing with planetary orbits we may treat the planets as moving mass points in the first approximation but if we are sailing in a lake or driving on a road the local geography is very important. It is therefore not surprising that physical science takes on many points of view and many aspects. But amongst them we may distinguish two dominant themes: the materialistic, chemical, structural tradition inherited from chemistry: and the abstract, mathematical functional tradition inherited from mechanics. In the development of physics these two traditions complement each other and enhance each other.
The Structuralist Tradition
In the first tradition we can ask what is matter made of? Studies in chemistry lead us to believe that all the myriad substances that are found on the earth can be composed from a few chemical elements combining with each other according to a set of (empirical) laws, some combine eagerly, some reluctantly: flourine, carbon, oxygen, chlorine, hydrogen all combine readily while gold, platinum, argon, helium, etc. combine only with great reluctance. Some elements like carbon, silicon, hydrogen, nitrogen and oxygen are plentiful on earth while some like gold and platinum are rare. (Some plentiful elements like carbon have special allotropic forms like diamond which are rare!) The multitude of chemical elements and their groupings into families like halogens, alkali atoms, alkaline earths etc. suggests that far from being indivisible they are composite objects and their qualities depend on the components and their qualities.
The study of the composition of the atoms became the discipline of atomic physics, which began with spectroscopy. (Each atom emits its own characteristic spectrum which serves as its signature). It was soon found that electrons were constituents of every atom; and that most optical and chemical properties could be understood as aspects of the behaviour of electrons. This great unification had a price: we had to develop the strange discipline of quantum mechanics with noncommuting quantities being used for representing dynamical quantities like position, momentum or energy. At the same time quantum mechanics elevated the mystery of light emission and absorption by atoms. Light is not a constituent of atoms but is associated with its functioning; it is a vibhuti rather than an amsa.
The atom shorn of its electrons is the (atomic) nucleus: and the various nuclei are themselves composed of neutrons and protons. This is the realm of nuclear physics: to understand the structure, properties and spontaneous reactions of various nuclei. While chemical forces could be traced to the electrical interactions between electrons there is a new force which must exist between the nuclear particles. This new kind of force was eventually understood to be the result of the spontaneous creation and absorption of particles called mesons. In the beginning one hoped for one meson (or one multiplet of similar mesons) but today we seem to need a great many!
Such a multitude of ‘elementary’ particles suggest that these particles are themselves not elementary but composite. What are they composed of? The present picture is that they are composed of a family of quarks. Quarks have not been found experimentally despite diligent searches. So efforts are being pursued to construct a theory in which the elementary objects would not be observable at all!
The odyssey thus ends in a curious place. The essential ingredients of all tangible concrete matter are ultimately unobservable in principle.
In these searches for the basic constituents, experiment and theory have gone hand in hand: new sophisticated techniques have been developed for experiments with superfast computers as an essential link. But theory also has had to develop new tools: quantum theory itself and the mathematical disciplines of group theory and algebra in infinite dimensional spaces.
The story is not complete without weak interactions and gravitation. Of these gravitation is truly universal; and is therefore treated as a modification of the behaviour of the space-time manifold. Space-time itself became a dynamical entity capable of sustaining vibrations. Once this is accepted Cosmology is within reach. Cosmology becomes a part of standard physical science.
This programme reveals new interconnections between the very large and very small. If the universe is dynamical conditions at earlier epochs may be much different from what it is today. There is then the possibility that in the far past there was a stage in which matter and light were compressed into very high density, from which stage we have an explosive expansion. On the basis of such a picture we can attempt to compute nucleo-synthesis rates and the chemical abundance of elements at the present time. Thus what was a ‘given’ in chemistry becomes a computable quantity in physical cosmology; by the way, apart from the agreement that the observed abundances of various elements it also explains that this composition is valid throughout the universe, except perhaps in the interior of the stars where thermonuclear reactions are still taking place.
A by-product of such a view is the prediction that there should be a cosmic microwave background; several decades after this prediction it was discovered experimentally.
The Functionalist Tradition
The other tradition in physics is that of abstract functional description of matter. We say ‘wind blows’ and are talking about wind, detect wind velocity and direction yet we also know that wind is but air in motion. Waves are water (or other fluids) in motion. We thus invent new categories because it is convenient to describe what is ‘observed’. It is a time honoured tradition: Newton’s laws of motion are about ‘bodies’ or ‘particles’. What are these? They are those that move. The process of motion is best viewed as the motion of something. Energy is that which is conserved: when energy of motion is converted into heat we talk of the conservation of energy and view energy as a permanent entity which only changes from one form to another much like chemical elements combine with, substitute, or dissociate from a chemical compound. The eternal verities are not directly observed but their manifestations are!
When electromagnetism was properly understood to have wave-like vibrations people were ready to invent a mysterious ‘aether’: that does the vibrations. When quantum theory has states that exhibit wave-like properties some people worry about what is the medium in which the vibrations take place.
It takes some degree of insight and experience to recognize that the equations of motion themselves suffice to make a model of reality. Newton’s equations are the model of physical reality: a ‘particle’ is that which has position and momentum and hence realizes the motion. Position and momentum are variable but no particle is seen without some position and some momentum. Once one realizes this way of recognizing a particle the way is open to deal with chaotic and ‘mixing’, motion where the notion of a particle trajectory is not very useful and one has to consider phase space ‘flows’.
Electromagnetism is described in classical theory by Maxwell’s equations. What is the ‘object’ described by these equations? What is the realization of these dynamical laws? The present style is to call this the electromagnetic field which is nothing but space-time equipped with potentialist. This field, ksetra, is the dynamical entity.
Quantum mechanics advances such abstractions one step further. The quantum particle is that which is described by Schroedinger’s equation. The physical state is best described by a complex-valued wave function. This object has only some similar features to Newton’s ‘particles’ there is a limitation to the degree of precision with which the position and the momentum can be assigned described by the uncertainty relations of Heisenberg:
Dq Dp < ½
and of Schroedinger:
(Dq)2 (Dp)2 — (D(qp))2 < ¼
These uncertainty relations are the price we pay for using an inappropriate description: much like the distortions in a map of the spherical earth on a plane sheet of paper, where whatever we do there are distortions. We can trade one kind of distortion for another. Mercator’s projection gives the directions correctly but greatly distorts the higher latitude areas. Polar projections represent the neighbourhood of the pole accurately but vastly distort the other hemisphere. Bartholomew’s projection tears up the map in various locales while Buckminister Fuller’s projection distributes these tears more uniformly with small triangular regions rendered faithfully. No one causes these distortions: Alaska and Kamchatka appeared on opposite ends of the world map that we used in school, but clearly they are close together on the earth!
When we penetrate to the subnuclear level particles occur in multiplets which are identified as representations of symmetry groups. The neutron and proton furnish a two-dimensional representation of the isospin group of which the pi-mesons (whose exchange between nucleons cause the longer range part of the nuclear force) furnish a three-dimensional representation; and the deuteron (the nucleus of heavy hydrogen) furnishes a one-dimensional representation.
An extension of group theory is to the theory of gauge groups which may be thought of as "field of groups", a group at each space-time point. Whenever such a group is postulated there are gauge particles that correspond to them and gauge interactions between the various particles. Modern particle physics makes use of such gauge forces to account for most of the particle reactions.
While these two approaches are different they do not contradict each other; on the contrary they enhance and supplement each other. Nevertheless, when one talks about a physics of matter, we must recognize these two threads of ideas. It becomes even more important when we compare contemporary physics with knowledge in the Indian tradition.
Before concluding this section I must point out that quantum mechanics and particularly quantum particle physics have erased the category difference between substance and process, between particles and interactions. Interactions are carried by particles which binds particles together which in turn modifies the interactions. Forces and particles are but two manifestations of the dynamical system. Since processes are noncommutative and often depend upon their sequence, so do observations of dynamical attributes. The Heisenberg-Schroedinger uncertainties and their generalizations are expressions of this noncommutativity.
Vaisesika and Sankhya: Structuralist Traditions
In the Indian tradition we find these two threads. In the Vaisesika system of philosophy we find the closest parallel to the chemical physics approach; to describe matter in its elementary and composite forms, the qualities (gunas) of the fundamental kanas (quanta) and the primary substance (dravya) of the universe. There are nine of them: Earth (prthivi), water (jalam), Air (vayu), substratum (Akasa), Time (kalam), Space (dik), Mind (manas), radiation (tejas), and self (atma) are these nine. Note the prophetic inclusion of space and time anticipating modern cosmology and the use of the substratum (akasa) as distinct from it. But Vaisesika system goes beyond it in including mind and the self as relational entities so that the world is treated as a perceptual discipline. The dravyas are but the raw material for the world-building: one must include the relationships: Quality (guna) was already mentioned; Action (karma) which are dynamical relationships including static stable situations; Universal (samanya) properties, ‘beingness’ Individuality (visesa), the distinguishing characteristics, necessary intimate relations (samavaya); and Negation (abhava). The first four dravyas: Prthivi, Jalam, Tejas, and Vayu are divisible and their elementary indivisible units are the paramanu or kana (quanta). These four dravyas together with Akasa constitute the five Bhutas (pancabhuta).
The ultimate particles of the four dravyas are endowed with quality by virtue of which they can coalesce: either primary or secondary (molecules?) of the same elements or of distinct elements. When threads come together we have aggregation (samyoga); but when it is woven into a fabric we have the fabric itself as a new creation, non-existent until then; this new relationship is merging (samavaya). Spatial extensions of ponderable bodies arose from them being composed of secondary compounds and not due to the extension of the atoms.
What is created can also dissolve. All creations are impermanent and the association of two or more dravyas will unravel eventually echoing Nagarjunas aphorism: All that is composed shall decompose!
It is also noteworthy that self (atma) is plural and is a dravya.
Sankhya system begins with two primary functionalities: Sentience (purusa) and Nature (prakrti). The Sentience is without specific qualities, discriminating (judgemental), alive (spontaneous), free of entanglements, beyond causality but plural; in contrast Nature both in its manifest (vyakta) and unmanifest (avyakta) aspects is non-discriminational (non-judgemental), universal, not spontaneous and entangled in transformations. Nature is also endowed with three fundamental qualities (guna): integrity (sattva), dynamism (rajas) and inertia (tamas). This Nature undergoes a sequence of modifications and the later stages include ego (ahamkara), mind (manas), subtle elements (tanmatra) and gross elements (bhuta). Nature in its state of dissolution (pralaya) has all the gunas in balance; by the very presence of the sentience (purusa) integrity (sattva) dominates and intelligence (mahat) arises, which in turn yields Ego (ahamkara). Mind (manas) is then born, and sensory organs, motor organs, subtle elements and gross elements. From vibration (sabda) arise the substratum (akasa), from vibration and contact (sparsa) arise air (vayu), from vibration, contact and colour (rupa) arise radiation (tejas); adding taste (rasa) yields fluid (ap); finally including smell (gandha) yields earth (prthivi). Sankhya system also has a novel way of dealing with causality; the effect is merely the gross manifestation of that which was subtly present in the material cause.
Finally, according to Sankhya, sentience is not to be sought for in matter; nor do Intelligence (mahat) or Mind (manas) come from matter alone. Sentience is reflected in Nature to generate Intelligence and Mind, and even the sense and motor faculties.
Since Yoga and Purva-Mimamsa are primarily concerned with individual spiritual discipline I shall not comment on them here except to note that Yoga sutras clearly points to the possibility of perception being refined to the point that the individual awareness can transcend the limitations of material laws.
Uttara-Mimamsa: The Functionalist Tradition
Uttara-Mimamsa philosophy as contained in the Upanisads is clearly akin to the functionalist tradition in physical science (or rather the other way around!). This is a vast area of literature and therefore I have to content myself with a few characteristic examples.
The Aitareya Upanisad has a graphic account of creation: how Prajapati created a sentient being out of a blob (pinda) and then created the sense principles (devata), their sense-organs; and how the sense principles told Prajapati that they were hungry and needed nourishment and in response food was created but to no avail since no sense-organ could consume it; and how finally the downward vital breath (apana vayu) was able to assimilate the food and nourish the sense-organs and the sense principles. It sounds like a fanciful legend about creation unless you happen to recognize in it the perception of the world by someone waking up from deep sleep. The downward breath, the prana that digests the food in one that liberates the nourishing chemical energy necessary to sustain life. It is the first explicit account of the Second Law of Thermodynamics and its sequel that of dissipative structures. It is only in recent years that Prigogine has brought to our attention the essential role played by dissipation in the creation of new structures in open systems.
The variability of the perceived universe in different states of awareness is the opening subject of the Mandukya Upanisad. In the waking state (jagrat) the person is outward directed and the sense-organs perceive the "external universe" and feeds this information to the mind and the mind builds up its world-view. But when one is dreaming (svapna), even though similar processes take place the person is inward directed. In non-dreaming sleep (susupti) all perceptions are negated. What happened to the waking person or the dreamer? When one wakes up from a dream where does the dreamer go? Where did he come from? Mandukya goes on to identify the Self as the integration of all this, yet beyond all this. When one sees stereoscopically, two different visions are merged into one and the object viewed acquires a new dimension: the view is neither picture, nor the two alternately or a collection of them both. Yet the three-dimensional perception subsumes the individual views and they can be obtained by projection. So too, the world is transmuted when different perceptions are integrated.
The two aspects of experience, one as an involved doer and one as awareness unsullied and unentangled implicit in Mandukya is made explicit in the Mundaka Upanisad. Here there is the metaphor of two birds in amicable ambience perching on two branches of the same tree: one partaking of the sweet and the bitter fruits while the other merely looks on. In Chandogya Upanisad there is a discussion on the nature of light: What is the light with which we see when the sun has set, the moon is obscured by clouds and the fire has gone out? It is obviously not a discourse on optics but on perception. In Katha Upanisad the young boy Nachiketa asks the Just Lord (Yama dharma raja): Where do people go when death has overtaken them? The subsequent discourse is a systematic exposition of the hierarchy of perception and transformations much like in the Yoga sutra.
The non-Vedic Jaina and Buddhist systems also treat world-views in characteristic ways. The Buddhist views are closest in methodology with modern science in its phenomenological discussion and the care with which causality is treated. I will not be able even to outline these systems. I shall content myself with pointing out that all these traditional systems do allow for intention (sankalpa) which would enable one to transcend: whether it be from the misery of unfulfilled lives, from unsatisfied desires or irremovable attachments. So not everything can be predetermined: there is to be an element of freedom. Without it there is no liberation (moksa) or freedom from attachments (kaivalya). The purpose of all these systems is happiness: and practice of the discipline is to restore to us our true nature; and our true nature is happiness. Anandeti abhyasat: anandam brahmah. In this one essential aspect the Indian philosophic systems, explicitly theistic or otherwise, differ and stand above contem-porary science. Contemporary Science looks in terms of utility (technology and standard of life) or, in rare cases, the joy of creativity. But never does it aim to see uninterrupted happiness as the aim of all disciplines, including the discipline of science. Science is not yet seen as a spiritual discipline. In the Indian tradition not only the systems of philosophy but even other disciplines like grammar, politics, music or dance, all of them are for restoring us to happiness. There seems to be nothing incompatible with or contrary to scientific principles so to enlarge science.
©1995 Indira Gandhi National Centre for the Arts, New Delhi