In some ways, time is such an easy concept. You ask someone what time it is and they know exactly what you are referring to. They answer and thats exactly the answer you were looking for, no miscommunication, perfect understanding. And yet if you dig a little deeper there is another question which is quite disturbing. What is time?
We define time an a measure to sequence events and capture interval between events. It defines temporal position of events and its continual movement. So far so good. However, if we use this to answer some other questions for e.g. beginning on the universe and what was before that? when did time start, how can time start? Our logic and definition does fall apart and these questions become unanswerable.
So what is the problem here? Answers in my view lie in how we define time. Lets look at something we consider similar to time. Our three spatial dimensions. I am looking up into my room, what do i see? Do i see height, width, depth? No, I see space?. The three dimensions in reality is just our interpretation of space. This phenomenon known as "Transcendent Ideality" was introduced by Kant where he stated that any form of appearances e.g. space and time are ordered in certain relations i.e. any interpretation is combination of sensation (input to senses) and cognition (thought) rather than something that exists independent of mind.
Kant's explanation only answer part of the question, i.e. how we interpret things. But the question of what time and space really are was answered quite convincingly much earlier. That was by Leibniz in late 17th century when he said that space or time don't exist in reality but are merely something we use to define relation of objects. There is no absolute location of space or time but only relative to a location or event. We sometimes confuse the convenience of space or time with actual reality i.e. we think space and time actually exist. I find that not only is this completely logical but also helps answer some more difficult questions on other philosophical topics.
While this may seem quite basic and logical we quite often forget it. Otherwise we would structure our "Time travel" , "Beginning of the Universe" and "God & time" debates quite differently.
