Atomic Theory of Ancient India (भारतीय परमाणु-विज्ञानम्)

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Atom 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.

Nyaya-Vaiseshika Atomic Theory

The Atomic Theory of the Nyaya-Vaiseshika system explains the order of creation and destruction of non-eternal objects. According to this theory only the composite substances of the atoms of earth, water, air and fire which 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 chemical theory of the Nyaya-Vaiseshika system involves the theory of Anu-s or atoms comparable to the tanmatras of the Samkhya philosophy. The Samkhya virtually substantizes the “gunas”; the Vaiseshikas take them to be qualities which are always found in some dravya. According to Maharshi Kanada, every material of this universe is made up of kana or parmanu (atom) which are invisible, indivisible, eternal and indestructible. There are two states of anu- a state of motion and a state of absolute rest.

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).

Each of the first five substances possess a unique quality, which makes the substance what it is. Maharshi Kanada recognized 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 partless 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 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. 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 the Ancient Indian Atomic Theory:

• Indivisibility: Parmanu are considered the smallest, indivisible particles, the limit of division for matter.
• Eternal and Unchangeable: Atoms are eternal, unchangeable, and the basis for all material objects.
• Four Elemental Atoms: The theory posits four elemental atoms: 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.

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. 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.