A person remembers the past and wonders about the future. An older person thinks how quickly time has passed, and that it seemed just yesterday-perhaps even a moment ago-that they were as young as the youth they see around them.
Yes, as the expression goes, time seems to "fly by"-but does it? On the other hand, people describing some great moment of inspiration have said or written that it was as if "time stood still."
On this physical earth plane and dimension of existence, in order to have existence as a person perceives it with his or her outer senses, it is a world of opposites-and that includes what seems to appear as past and present.
With mystical awareness, there is the reality that past and present on this earth plane are opposites, but when one is in Universal Consciousness, God, Oneness, or Absolute Reality, there are no opposites. There is simply the Eternal Moment of Beingness-a singular moment of God's Eternal Contemplation, "I AM."
Eventually, whether in this physical lifetime or another, we become aware of the various states of our beingness; and through the Grace of God's Presence, we integrate all levels into a harmonious working Wholeness of Beingness.