Ancient Indian Physics (भौतिकविज्ञानम्)

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Ancient Indians contributed to the development of many concepts of modern Physics (Samskrit: भौतिकविज्ञानम्) much earlier than the advent of modern physics. The study of physics involves an understanding of the functioning, interactions and relationships between the fundamental components of the observable universe and the observable cosmos. The field of physics covers all aspects of the natural world, both at macroscopic and microscopic levels. The conception of Panchamahabhutas or the five gross elements to explain the diversity of nature was the foundational aspect of Indian physical shastras. Nature consists of a variety of things - solids, water, gas, fire, and space. Space or Akasa is considered eternal and was created to give material objects a positive reference, a substratum, a medium on which things exist. In modern terms it resembles the concept of all-pervading ether medium.

Electricity, light, heat, mechanics (motion and inertia of things), gravitation, sound and its transmission, and quantum physics which comprise the subjects of modern physics have been explored in several Indian traditions along with their applications.

Introduction

Physics deals with matter and energy and their interactions. Measurements are central to the growth of physics and length (space), time, and mass, are the three most important physical quantities, called the fundamental quantities. Most other physical quantities are generally expressed in their terms of mass, length, and time. For example, speed is measured in miles per hour (or kilometer per hour) and involves a measurement of space (distance) and time.

Matter and Mass

In order to define and distinguish matter, Kanāda defines matter or substance into padarthas or six categories (Vais. Sutr. 1.1.4)

1. Substance (dravya)
2. Quality (guna)
3. Action (karma)
4. Generality (sāmānya)
5. Individuality (viśesa)
6. Inherence (samavāya)

Matter of different materials have different attributes. For example, identical sizes of iron and cotton would have different weights. Apples can have differences in their colors and yet be called apples. It is the assembly of attributes that defines matter. Maharshi Kanada describes seventeen attributes or gunas of matter and each of the bhutas or elements have special characteristics:

• रूपरसगन्धस्पर्शवती पृथिवी । वैशेषिक-२,१.१ । Prithvi (Earth) has the attributes of color, taste, touch and smell
• रूपरसस्पर्शवत्य आपो द्रवाः स्निग्धाः । वैशेषिक-२,१.२ । Ap (Water) has the attributes of color, taste, touch, fluidity and viscidity
• तेजो रूपस्पर्शवत् । वैशेषिक-२,१.३ । Tejas or Agni (Fire) has color and touch
• स्पर्शवान् वायुः । वैशेषिक-२,१.४ । Vayu (Air) has only touch
• त आकाशे न विद्यन्ते । वैशेषिक-२,१.५ । Akasa (ether) has no attribute of touch

Air is matter, but its non-perception in spite of being a dravya is due to the non-existence of color in it. With the non-perception of air, Kanāda defines reality beyond appearance. Not all that exists in the world is visible to human eyes. In his attempt to clarify a difference between space and air, Kanāda used the attribute of touch which is absent in space: “Air has the property of touch while space does not have such a property.”