It was Chrysippus who best put it that only the present exists. We may have lived in the past and we may be looking forward to the future but we only live for now. If I was asked what is time, I would know what it was, but if I was asked to explain it, I wouldn't be able to. There is no concept of time. We drift through time endlessly but no one actually knows what it is. The most important thing however is to know that we are living with time in the present, in the here and now. Without time there would be no present, therefore no past and no future. But we can not mistake the past for the present. We do not live in the past. We all have experienced it but we no longer live it, thats why what ever we have done up to this very moment is in the past and what we do every second thereafter, fades into the past, and we still carry on moving forwards into the future, but we never live in the future. As the future draws closer it suddenly becomes the present and the moments we just lived become the past. Therefore time exsists as we do, to this very moment with everything we do and every action we take. We need time to distinguish our days and our nights, to know where morning begins and darkness falls.
Without time we would fall into one long hour after another, into one long day. Our days would not be broken up and our body clocks would malfunction. This is why time exsists. And it is why we do have a past and we do have a future, because of time. After researching many sources I have come to find that Andre Comte-Sponville explains it best when he says to make the most of life we have to live but not just live, live in the present. We can not look at whats already been as there is nothing we can do to change it, and we can not live in the future as it does not exsist yet. We can only progress by living in the present. But Andre Comte-Sponville also comments on not mistaking living in the present to living in the moment, as these are very differnet from each other as living in the moment is compromising our ideas and beliefs. We need to live life spontaniously not plan for every moment we live.