Jethalal S. Zaveri
Prof. Muni Mahendra Kumar
The idea of the smallest indivisible ultimate building blocks of matter first came up in connection with elaboration of the concepts of Matter, Being and Becoming, which characterised the first epoch of Greek philosophy. The fundamental question was 'what is the material cause of all things?' Simultaneously, there was a demand that this question be answered in conformity with reason, without resort to myths, mysticism, or superstition.
Greek philosophy and science, which were not originally separate, were born together at the beginning of the sixth century B.C. with the first of the Milesian philosopher, Thales. He took his view primarily from meteorological considerations and held that "WATER is the material cause of all things."
Of all things we know, WATER can take the most diverse shapes; it can take the form of ice and snow, it can change itself into vapour and can form clouds, it seems to turn into earth where the rivers form their delta, and it can spring from the earth. And to add to all this, water is the condition - a must - for life to exist If there was such a fundamental substance at all, it was natural to think it to be of water as out of this all others are formed.
Anaximander, second philosopher of the Milesian school and a pupil of Thales, did not accept water or any other known substance. According to him the primary substance was infinite, eternal and ageless and it encompassed the whole world. This primary substance, according to him, was transformed into various substances with which we are familiar and these were transformable into each other.
Anaximenes, the last of the Milesian triad (500 B.C.) taught that AIR was the primary substance. "The soul is air, fire is rarefied air, when condensed, air becomes first water, then earth and finally stone." Thus he introduced the idea that the process of condensation and rarefaction caused the change in the primary substance. The condensation of water vapour into clouds was an obvious example and of course the difference between water vapour and air was not known at that time. The Milesian school of thought is important not for what it achieved but for what it attempted. The speculations of Thales, Anaximander and Anaximenes are to be regarded as scientific hypothesis. The next stage in Greek philosophy is more religious but less scientific.
Heraclitus (500 B.C.) was a mystic of a peculiar kind. He regarded FIRE as the basic element everything like the flame in a fire is born by the death of something. He taught that the world is at once one and many. There is unity in the world but it is not unity forming the combination of opposites. The strife of the opposites is really a kind of harmony and 'the opposite tension' of the opposites constitutes the unity of the one. He believed jn perpetual change that all things are in a constant state of flux, this flux being due to an everlasting conversion of matter into energy and energy into matter, everywhere over the vast stretches of the material universe.
At this point, let us pause for a while and compare the findings of the ancients with the modern. Firstly, the problem whether the primary substance can be one of the known substances or must be something essentially different, occurs in a somewhat different form in the most modern part of atomic physics. The physicists today try to find a fundamental law of motion for matter from which all elementary particles and their properties can be derived mathematically. This fundamental equation of motion may refer either to waves of a known type, proton and meson waves or to waves of an essentially different character which have nothing to do with any of the known waves of elementary particles. In the first case, it would mean that all other elementary particles could be reduced in some way to a few sorts of 'Fundamental' elementary particles. In the second case, all different elementary particles could be reduced to some universal substance, which we may call energy or matter, but none of the different particles could be preferred to the others as being more fundamental. The later view, of course, corresponds to the doctrine of Anaximander and in modern physics; this view is perhaps the correct one.
Next, Heraclitus holds that the change itself is the fundamental principle and is represented by FIRE as the basic element which is both matter and a moving force. Modern physics is, in some way, extremely near to the doctrines of Heraclitus. If we replace the word 'fire* by the word 'energy' we can almost repeat his statement word for word from our modern point of view. Each manifestation of energy involves either matter in motion or a change in its physical state, which we designate as physical energy; a change in the chemical constitution of matter, which we know as chemical energy; or a combination of the two. Physical energy can be converted into chemical energy and vice versa. The chemical energy stored in the plant manifests itself by an increase in the plant as weight as compared with that of its original constituents. Similarly, the release of energy manifests itself through a loss in the total weight of the plants as substance. Energy is, in fact, the substance from which all elementary particles, all atoms and therefore all things are made, and energy is that which moves. Energy is a substance since its total amount does not change, and that the elementary particles can actually be made from this substance is seen in many experiments on the creation of elementary particles. Energy can be called the fundamental cause for all change in the world. But comparison of Greek philosophy with the ideas of modern science will be discussed later.
Parmenides (450 B.C.) denied the existence of empty space for logical reasons. Since all change required empty space, as he assumed, he considered change to be impossible, and regarded the changes perceived by us as mere illusions of the senses. Parmenides was in strong opposition to Heraclitus, and where Heraclitus maintained that everything changes, Parmenides retorted that nothing changes. What the subsequent philosophy accepted from Parmenides was not the impossibility of all change but the indestructibility of substance. The concept -of an indestructible substance as the substratum of varying properties grew out of this philosophy, and became one of the fundamental concepts of western thought.
Empedocles (440 B.C.), younger contemporary of Parmenides changed for the first time from monism to a kind of pluralism. He assumed four basic elements: Earth, Water, Air and Fire. Each of these were everlasting but they could be mixed together in different proportions and separated to form the varieties of things and thus produce the changing complex substances that we find in the world Here for the first time, the idea is expressed that the mixture and separation of a few substances, which are fundamentally different, explains the infinite variety of things and events.
According to these views, the soil, for example, was a combination of earth substance and water substance closely mixed, atom-by-atom. A plant growing from the soil combined earth and water atoms with the fire atoms coming from the rays of the sun to form composite molecules of wood substance. The burning of dry wood from which the water element was gone, was viewed as decomposition or breaking up of wood molecule into the original fire atoms, which escape in the flame and the earth atoms which remain as the ashes.
Anaxagoras (462-422 B.C.), a contemporary of Empedocles, took the next step towards the concept of atom. He assumed infinite variety of infinitely small seeds (not the four elements of Empedocles. but innumerably many different seeds), which were mixed together and separated again to create multiplicity of things. The seeds may change in number and in relative position. All seeds were in everything; only the proportions might change from one thing to another.
