Bharatiya Jyotihshastra (History of Indian Astronomy), translated by R. V. Vaidya v1.c5.38

v1.c5.38

The sun and the moon rise and set regularly everyday. The seasons like summer, the monsoon, and other seasons also recur in their regular order. Today, however, we are not struck with wonder at these phenomena because of our familiarity with them; but the primitive man at the beginning must have been overwhelmed with wonder at the regular recurrence of these phenomena, and his inclination must have been drawn to the study of the earliest times. The sun rises in the morning. It slowly comes up. After some time it reaches the highest point in the heavens, and then goes down slowly and the rays of the sun gradually lose intensity of heat till such time as the sun vanishes. Then follows the darkness which continues for a long time. Next day, the sun rises again almost at the same point and not in any direction at random. The observer then wonders, "Is it yesterday's sun which has risen today or is there a new sun rising every day ? If it be the same sun where did it dwell at night ? Why does it not rise in any direction at random ? Why are its hot rays vary in intensity ? The sky appears to touch the horizon at the place where the sun rises; then how it is that the sun comes above out of that very place ? If there be an ocean in the east and an ocean in the west, the sun appears to be emerging from one and plunging into the other; does it really sink in the ocean ?" We do not attach any importance to such thoughts today ; but in the beginning human mind must have been haunted by these thoughts and much time must have elapsed before any of these problems could have been finally solved. The knowledge of human being grows by tradition and the experience of the past and this proves useful to the posterity. Even in modern times, year after year rolls by till we come across a new discovery, which might eventually seem to be trivial but at the time of ts invention it is taken as an established truth.