Atomic Theory of Ancient India (भारतीय परमाणु-विज्ञानम्)

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Atom (Sanskrit: परमाणुः) has been described as the smallest, indivisible particle in any substance. Science and philosophy have studied through investigations and experiments, the many forces of nature, such as gravity, electromagnetism, nuclear forces etc., but one of the major theories studied is that of the atom.

In Indian thought, there are two naturalistic theories of the origin of the empirical world. One view accords world to be a product of ordered evolution from an original undifferentiated Nature (one becoming many), while the second views world arising out of atoms combining together in various ways (many becoming one) in a limited sense. The Sankhya represents the first, and the Vaiseshika the second view.

Nyaya-Vaiseshika Atomic Theory

The Atomic Theory of the Nyaya-Vaiseshika system explains the order of creation and destruction of non-eternal objects. Nyaya-Vaiseshika is noted for their logically-structured atomism. According to this theory only the composite substances of the atoms of earth, water, air and fire are produced and destroyed. Atoms are the fundamental building blocks of matter, and the universe consists of multiple entities, both material and spiritual, making up its ultimate constituents. The concept of avayavin (whole) and avayava (constituent part) has shaped the atomic theory of the Nyaya-Vaisesika. This school of thought uses a logical and causal framework to explain how invisible particles combine to form the visible universe.

Attributes of Atoms

According to Maharshi Kanada, every material of this universe is made up of kana or parmanu (atom) which are invisible, indivisible, eternal and indestructible. They possess certain characteristic properties and potentials of sense stimuli.

The Vaiseshika sutras, define and explain the nature of dravya or substance, and classifies all dravyas or things of the world into nine: Earth, water, fire, air, ether/space, time, space, atman and manas (mind).

Among these nine, the first four, namely, earth, water, fire and air are considered to be atomic in nature. Each element has own class of atoms with particular attributes by which they can be differentiated, i.e., qualitatively. Maharshi Kanada recognized them as four kinds of atoms each having a unique quality or guna

1. kshiti or earth - smell
2. apa or water - taste
3. tejas or fire - color
4. vayu or air - touch

These four are knowable by outer perception. The substances of earth, water, fire, and air are eternal and non-eternal. The atoms of these four substances are whole (avayavin) and eternal, because as partless they can neither be produced nor destroyed. The fifth substance, akasha or ether, has the characteristic of sound and is indivisible, eternal, and non-perceptible. Akasa (ether), according to Maharshi Kanada, has no atomic structure; it is inert and ubiquitous serving only as the substratum of sound which is supposed to travel in the form of waves in the manifesting medium of vayu (air). Atoms are the primordial infinitesimal particles of everything except space or Akasha.

Kshiti or earth has fourteen qualities

Each atom has its individual characteristics, and it combines with other atoms to form the larger entities similar to molecules. These atoms are characterized by their characteristic mass, number, quantity, basic molecular structure such as dyad, triad, etc, fluidity (or it’s opposite), viscosity (or its opposite), velocity (or quantity of impressed motion- Vega), elasticity, gravity, and other characteristic potential color, taste, smell or touch not produced by chemical operation. It is these four kinds of atoms involved in all chemical reactions while the space remains unaffected.

That matter is ultimately made of indivisible building blocks, thus appeared in India as part of philosophical school of thought long before Western inventions.

Key Features of Atomic Theory

Key Features of the Ancient Indian Atomic Theory based on Nyaya and Vaiseshika texts:

• Indivisible: Parmanu are considered the smallest, indivisible particles, the limit of division for matter. They have no constituent parts (avayavas) and cannot be further divided.
• Eternal and Unchangeable: Atoms are eternal, unchangeable, and the basis for all material objects.
• Qualitative Differentiation: The theory posits four elemental atoms based on the four eternal elements: earth, water, light, and air.
• Atoms as Building Blocks: These atoms combine to form larger molecules, called "dvyaṇuka" (binary molecules), and then further combine to create various substances.
• Chemical Change: Chemical reactions, such as changes in color of heated mud utensils, are attributed to the combination and rearrangement of atoms.
• Properties of Atoms: Atoms of the same element have identical properties, while different elements have different types of atoms.
• Indestructible: Atoms are indestructible and cannot be created or destroyed.
• Eternal motion: Atoms are in a state of constant motion.
• Spherical Shape: Despite having no magnitude, atoms are theoretically regarded as spherical (parimandaliya)
• Without Magnitude: They are conceived as having no length, breadth, or thickness (infinitesimal), but their combinations produce matter of visible magnitude.

Maharshi Kanada further logically explained that density of atom in water is more than air. He also gave the theory of chemical changes and claimed that chemical changes occur because of the various factors and especially due to variations in temperature.

Combination of Atoms

Atoms may conjoin or disjoin in reactions. The atoms of the same bhuta (element) combine driven by an inherent tendency which is their natural property to form dyads according to Prashastapada. It represents the formation of binary molecules of elementary substances according to our modern conception. These binary molecules or dyads then combine among themselves by groups of three, four, five, etc., to produce larger aggregates in obedience to the moral law underlying the creation. Maharshi Kanada maintained that different atoms combine in different patterns, some in pairs, some in triads, tetrads etc.

Therefore, Prashastapada's Basic unit of n dyads ≡ 1 dyad + 1 dyad… n dyads where n ≥ 1

While Kanada's Atoms combine ≡ basic unit /molecule with two, three or n number of units

Atoms possess an intrinsic vibratory or rotatory motion (parispanda).

Effect of Heat

A substance may change qualitatively under the influence of heat in its course of existence. Heat and light, are the different forms of the same essential entity, tejas according to Vaiseshika. The Vaisheshika’s stand on such a change is that with application of heat a substance

- decomposes into original homogenous paramanus or the basic unit with zero mass (not the unit of dyad, triad etc)

- transformation of the character of the atoms

- recombination of paramanus with a new basic unit arrangement and order resulting in a new substance.

The Vaisheshikas hold that under the influence of heat, substances are broken down to the most basic entity (paramanu) before being transformed in to a new substance whereas the Nyaya school does not believe in decomposition in to the very basic entity.

Combination may also take place either between atoms of two or more substances belonging to the same or different bhuta classes.

(A) Mono-bhautic compounds :—These are the simplest ; i. e., compounds formed by the union of homogeneous atoms of different substances which are isomeric modes of the same bhuta class.

(B) Hetero-bhautic compounds :—These may be bi or polybhautic compounds formed by the union of heterogeneous atoms of substances belonging to the different bhuta classes.

A nature (Tattva) of the particular substance when it turns into another nature is called transmutation (Utparivartana) in scientific terms. A study on the Changes (Parivartana) and analysis (Visleṣaṇa) of the substance because of its origin and qualities is called Chemical Science of the particular substance. The Change is of two kinds such as

1) Physical Change (Bhautika Parivartana)

2) Chemical Change (Rāsāyanika Parivartana)

The first type of change i.e. the Physical Change, is when the nature of the substance undergoes changes due to various reasons for a particular period of time and returns back to its previous state. For example, a piece of Iron forms into magnet after a deep friction (Gharṣaṇa) on the magnet and returns into being a piece of iron after it loses the magnetic effect. In same manner, water turns into ice at the state of high cooling (Himānka) and returns to liquid state after melting.

In second type of change i.e. Chemical Change once the nature of the substance changes it cannot be reversed. For example, Milk turns into curd, and iron turns into rust etc.

Samkhya Theory of Matter

According to Samkhya the universe, as manifested evolved out of an unmanifested cosmic nature termed prakriti or avyakta, the ultimate ground. Prakriti, is an infinite, eternal, ubiquitous, indestructible, indifferentiated, indeterminate continuum. This was believed to be made up of infinitesimal reals or gunas, representing substances classified under

1. sattva (the essence or intelligence stuff)
2. rajas (the energy stuff)
3. tamas (the inertia or matter stuffs