In Timaeus (37d-39e), Plato argues that time is an emergent property of movement. If nothing moved, there would be no time. For Plato, every perception of time is a perception of movement: days are defined by the rising and setting of the Sun, years are defined orbits, and so on.
In Physics (4.10-14), Aristotle takes it one step further: time is a measure of movement, not the movement itself. It turns out that time is a human construct, not some intrinsic property of the universe. If there is no being (or “soul”) capable of counting and measuring movement, we would not be able to say that time technically exists at all.
Whether if soul did not exist time would exist or not, is a question that may fairly be asked; for if there there cannot be some one to count there cannot be anything that can be counted, so that evidently there cannot be number; for number is either what has been, or what can be, counted. (Physics 4.14.21-24)
Remember the old thought experiment about whether or not a falling tree makes a sound if no one is there to hear it? Aristotle invites us to apply a similar question to the whole cosmos, not just the forest. Can we rightfully say that “time” literally existed at all for 13.8 billion years before some conscious beings emerged that gave movements and durations the label of “time”? If Aristotle is right — and if we agree that time is more of an emergent property of consciousness than arising from orbital movement — then should we consider time and consciousness as more synonymous with one another than they are distinct?
What is time? In a sense, time is consciousness. All perception of time — past, present, and future — will cease upon the dissolution of your mind. Time is qualia. We all tell different stories of the past, experience the present in unique ways, and imagine various futures. Whether you speak of unicellular life 3.5 billion years ago or the future civilization you will leave as an inheritance to your children, you are talking about a subjective phenomenological experience that is inseparable from your consciousness.
I suppose, ultimately, this is just another way of reminding myself that efficiency and productivity never actually “save” any time at all — they are only distractions and preoccupations to which I surrender this tenure of conscious being.