Ancient India saw the relationship between knowledge of science and technology, with religion and social relations. The archaeological remains of the Indus Valley reveal knowledge of applied sciences. Scientific techniques were used in irrigation, Metallurgy, making of fired bricks and pottery, and simple reckoning and measurement of areas and volumes. Aryan achievements in the field of astronomy, mathematics and medicine are well known. Chinese records indicate knowledge of a dozen books of Indian origin. Brahmagupta’s Sidhanta as well as Charaka’s and Susrata’s Samhitas were translated into Arabic in the 9th or 10th centuries A.D.In ancient Indian mathematics was known by the general name of Ganita, which included arithmetic, geometry, algebra, astronomy and astrology.
It was Aryabhatta, who gave a new direction to trigonometry. The decimal system too was an innovation of India. By the third century B.C. mathematics, astronomy and medicine began to develop separately. In the field of mathematics ancient Indians made three distinct contributions, the notation system, the decimal system and the use of zero. The earliest epigraphic evidence of the use of decimal system belongs to the fifth century A.D. Before these numerals appeared in the West they had been used in India for centuries. They are found in the inscriptions of Ashoka in the third century B.C.Indians were the first to use the decimal system. The famous mathematician Aryabhata (A.D. 476-500) was acquainted with it. The Chinese learnt this system from the Buddhist missionaries, and the western world borrowed it from the Arab as when they came in contact with India. Zero was discovered by Indians in about the second century B.C. From the very beginning Indian mathematicians considered zero as a separate numeral, and it was used in this sense in arithmetic. In Arabia the earliest use of zero appears in A.D. 873. The Arabs learnt and adopted it from India and spread it in Europe. So far as Algebra is concerned both Indians and Greeks contributed to it, but in Western Europe its knowledge was borrowed not from Greece but from the Arabs who had acquired it from India. In the second century B.C. Apastemba contributed to practical geometry for the construction of altars on which the kings could offer sacrifices. It describes acute angle, obtuse angle, right angle etc. Aryabhata formulated the rule for finding the area of a triangle, which led to the origin of trigonometry. The most famous work of his time is the Suryasiddanta the like of which was not found in Contemporary ancient east.
During the Gupta period mathematics was developed to such an extent and more advanced than any other nation of antiquity. Quite early India devised a rudimentary algebra which led to more calculations than were possible for the Greeks and led to the study of number for its own sake. The earliest inscription regarding the data by a system of nine digits and a zero is dated as 595 A.D. evidently the system was known to mathematicians some centuries before it was employed in inscriptions. Indian mathematicians such as Brahmagupta (7th century), Mahavira (9th century) and Bhaskara (12th century) made several discoveries which were known to Europe only after Renaissance. The understood the importance of positive and negative quantities, evolved sound system of extracting squares and cube roots and could solve quadratic and certain types of indeterminate equations. Aryabhata gave approximate value of pie. It was more accurate than that of the Greeks. Also some strides were made in trigonometry, empirical geometry and calculus. Chiefly in astronomy the mathematical implications of zero and infinity were fully realized unlike anywhere in the world. Among the various branches of mathematics, Hindus gave astronomy the highest place of honour. Suryasidhanta is the best know book on Hindu astronomy. The text was later modified two or three times between 500 A.D. and 1500 A.D. The system laid down in the book can even now be used to predict eclipse within an error of two or three hours. The most renowned scholars of astronomy were Aryabhata and Varhamihira. Aryabhata belonged to the fifth century and Varahamihira to the sixth. Aryabhata calculated the position of the planets according to the Babylonian method. He discovered the cause of lunar and solar eclipses. The circumference of the earth which he measured on the basis of the speculation is considered to be correct even now. He pointed out that the sun is stationary and the earth rotates around it. The book of Aryabhata is the Aryabhatiya. Varhimihira’s well-known work is called Brihat Samhita which belongs to the sixth century A.D. Varhaihira stated that the moon rotates around the earth and the earth rotates around the earth rotates around the sun. He utilized several Greek works to explain the movement of the planets and some other astronomical problems. Although Greek knowledge influenced Indian astronomy, there is no doubt that Indian pursued the subject further and made use of it in their observations of the planets.Aryabhata wrote a book when he was barely 23 years. Varhmihira of the sixth century wrote a summary of five astronomical books current wrote a summary of five astronomical books current in his time. Brahamagupta of the seventh century A.D. appreciated the value of observation and astronomy and his book was translated into Arabic. One last great scientist was Bhaskara II. One of the chapters in the book Sidhanta Shiromani, dealing with mathematics, is the well-known work of Lilavait.Nevertheless, Indian views on the origin and evolution of the universe was matter of religion rather than of science. The cosmic schemes of Hindus and Jains in fundamentals were the same. All postulated a flat earth although Indian astronomers came to know that this was incorrect early in the Christian era. The idea of flat such remained for religious purposes.
Regarding astronomy proper it was studied as a Vedanta. Its name was Jyotisa. A primitive kind of astronomy was developed mainly for the purpose of settling the dates and times at which periodical sacrifices were to be performed. Several Greek words gained momentum in Sanskrit through knowledge of Greek astronomy. The sixth century astronomer Varahamihira called one of his five astronomical systems as Romaka Sidhanta. It is only western astronomy that introduced in Indian the sign of the Zodaic. The seven-day week, the hour, and several other ideas. Later, Indian astronomers made some advances on the knowledge of the Greeks and passed on their knowledge with that of mathematics via the Arabs to Europe. As early as seventh century, a Syrian astronomer knew of the greatness of Indian astronomy and mathematics. In the field of medicine, Aurveda was the contribution of India. Seven hundred hymns in the Vedas, particularly Atharva Veda, refer to topics of Ayurveda. Indeed, the whole approach was not scientific. The earliest mention of medicines is in the Atharva Veda. As in order ancient societies, the remedies recommended in it are replete with magical charms and spells. Medicine could not develop along scientific lines.
In post-Maurya time India witnessed two famous scholars of the Aurveda, Susrtua and Charaka. In the Susrutasmhita Susruta describes methods of operating contract, stone disease and several other ailments. He mentions as many as 121 implements to be used for operations. For the treatment of disease he lays special emphasis on diet. And cleanliness for Charaka wrote the Charakasamhita in the second century A.D. It is like encyclopedia of Indian medicines. It describes various types of fever, leprosy, hysteria and tuberculosis. Possibly Charaka did not know that some of these are infections. His book contains the names of a large number of plants and herbs which were to be used as medicine. The book is thus useful not only for study of ancient Indian medicine but also for ancient Indian flora and chemistry. In subsequent centuries Indian medicines developed on the lines laid down by Charaka. The Vedic hymns attribute various diseases to demons and spirits and the remedies for hymns prescribing correctly the symptoms of pulmonary tuberculosis, and connecting dropsy with heart diseases. However, national medicine began to 800 B.C. Medicine became a regular subject of study at centers like Taxila and Varanasi. The latter specialized in surgery. Susrutasmhita was compiled in the fourth century A.D. Charaka compiled the teachings of two of his predecessors who served at Taxila. Charaka and Susruta’s Samhits reached as far as Manchuria through translations in Tibetan and other Asian languages. In the eighth century A.D. these books influenced European medicine as carried over by two Arabs. Charaka Samhita was published as late as 1550 in Arabic.
Despite these achievements, medicine did not make any remarkable strides, for absence of dissection led to ignorance of anatomy and physiology. Indians were equally aware of the functions of internal organs such as lungs and brain. Surgery of some kind was even during the Vedic period. It was only from the time of Susruta that surgery came to occupy an important place in medicine. Surgical operations were performed like taking the fetus out of the womb, including caesarian, section, treatment of fistula, removal of stone from bladder and plastic surgery for the nose. Despite the developments as the above in medicine, ancient Indian doctors, in general had no knowledge of the functions of brain, although they knew the importance of the spinal cord and the existence of nervous system. Once again social taboos stood in the way of the growth of medical knowledge. It was a taboo to touch dead bodies. Despite the fact that the physiological knowledge of ancient Indians was very poor, Indians evolved empirical surgery. They knew bone-setting, plastic surgery and surgeons in ancient India were experts is repairing noses, ears and lips lost, or injured by mutilation. The physician was a respectable member of society as the Vaidyas were ranked higher in the hierarchy. Even to this day the rules of professional behaviour laid down in medical tests are almost the same as those of Hippocrates. Of course, some statements at one place state that the Physicians should not betray the patients and should be always of pleasant speech. In this context, he pleads that every day they must pray on rising and going to bed, since the work of the welfare of the all beings specially cows.
Regarding physics, it was closely linked with religion and theology and it even differed from sect to sect. Almost all religions believed that the universe consisted of elements like earth, air, water, and akasa (ether). Most schools maintained that there were as many types of atoms as there were elements. Some Buddhists conceived atom as the minutes object capable of occupying space but also as occupying the minutest possible duration of time coming into being and vanishing almost in an instant only to be succeeded by another atom caused by the first. This somewhat resembles the quantum theory of Planck. The Vaisesika School believed a single atom to be a point in space completely without magnitude. Further, most of the schools believed that atoms constitute molecules. However, the Indian atomic theories were not based on experiment but intuitive logic. The great theologian Sankara strongly argued against their existence. Beyond this knowledge of atoms, physics in India did not develop much. However, in the science of acoustics, India made real discovers. Based on experience for this correct recitation on Vedas, the human era was highly trained for the phonetic study – distinguished musical tones far closer than those of other ancient musical systems much earlier than other civilization.
Regarding chemistry and metallurgy too, some progress was made in ancient times. The Harappans developed metallurgy of copper and bronze about 2500 B.C. The Vedic Aryans tanned leather, fermented grains and fruits, and dyed scale production of copper, iron and steel, brass, silver and gold and their alloys. Indian steel was highly esteemed in the ancient world and it was exported in large quantities. Tin and mercury were imported and worked. And from the seventh century, alchemy was referred to in literature. The medical chemistry of ancient India did succeed in producing many important alkalis, acids and metallic salts. It is claimed by Bashama that ancient Indians ever discovered a form of gun powder. The coming of middle ages, Indian chemists, like their counterparts in the rest of the world, became increasingly interested in a specific remedy for all diseases, the source of perpetual youth, and even the surest means to salvation. Although they could not make precious metals, they could understand the chemistry of metallic salts. The heights attained by Indians in metallurgy and engineering are borne out by the almost pure copper stature of Buddha found at Sultanganj and the famous iron Pillar at Mehrauli (Delhi which has been able to withstand rain and weather for centuries without rusting).