To understand how to live in the moment, we need to have an understanding of time. Let’s look at time in a very simple but practical way: If you could divide time into three parts, you could say there was the past, the present and the future. At any given point, awareness can be functioning in one of these parts. Awareness can be in the “past” part of time and it can be absorbed in a conversation with a friend about the holiday you both took last summer to Italy, or awareness can be in the “future” part of time and it can be absorbed in talking with a friend about all the things you are going to do on your vacation to Paris that is coming up. If awareness is fully absorbed in what it is doing right this moment, then awareness is in the now or "present” part of time. So in order to live in the moment, all you have to do is bring awareness back to the present each time it wanders off into the past or the future.
