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We know time only from changes in nature. We observed that the earth turns around its axis and called it one day. Apart from that movement and its result, the changes in daylight, there is no justification for the idea of the day. Hours, minutes, and so on are only subdivisions of the concept “day.” We observe that the earth circles around the sun, and we call it a year. We watch a certain movement in nature and call the sum of instants that passed “time.” If for some reason the earth lost contact with the sun, our time units would become meaningless, and we would have to look for other changes in nature. Time is a conceptualization (vikalpa). Vikalpa is defined as a word that does not have a corresponding object. Time has no corresponding object in nature; it is merely deduced by the human mind, based on observation.
Our universe is said to be billions of years old and is predicted to last for another fifteen billion years. Prior to the Big Bang, all matter was condensed in one spot. Time is dependent on observation of change, an external reference point, and an observer. None of them can be ascertained prior to the Big Bang. This leads us to the conclusion that there was no time either.