Of the many philosophical assumptions in physics about the nature of reality, none is more mysterious than the existence of time. Unlike space, time does not have any of our five senses assigned to it. Our primary sensory mechanism, sight, creates a 3D world around us. Even in the absence of vision, hearing can place point sources in a 3D space. We have no built-in mechanism to perceive or sense time.
So what makes us sense time?
Time is sensed through change. We can best sense objects and movements at scales comparable to our body dimensions and speed. We can clearly see a person running, but not a bullet coming at us. We can appreciate the difference in size between an adult and a child, but not between two celestial objects or micro-organisms. Our sense of time is modulated by our life expectancy.
Time is Relative.
For suppose, if we lived forever, would we have a sense of time? If we did not have a sense of time, would that mean there was no time? Does time have an existence independent of our minds? More to our purpose in this book, would it be possible to do physics without a notion of time? Physics, as we know it today, (e.g., Newton’s laws of motion and the special theory of relativity) has time figuring prominently as an essential ingredient. A physics with no explicit time was attempted by Julian Barbour (in The End of Time), which shows that time is not essential. Time, however, makes it far more convenient to do physics.
Do animals have a sense of time? It is unlikely that they are conscious of their death. So, by our conjecture, they should not have a sense of time.
If you grew up on an island, without contact with other human beings, would you have a sense of time? It seems obvious that you would not have a language in the conventional sense of the word. Some philosophers believe that you would not even have any thoughts at all. But does the sense of time come before or after thoughts?
Time is unreal assumption like Mathematics we use. But that’s an extremely convenient tool, which we use to solve many problems in Physical Sciences.
This is the topic where we get more questions than answers. This is a never ending process. All of it cannot be discussed in a single post. This is just a part of it. Expect still more posts on Time.
I hope you like this above information about the Nature of Time. All that information is taken from bunch of different sources and if you are interested in learning more about TIME, check out the PDF of “A BRIEF HISTORY OF TIME BY STEPHEN HAWKING”