What Is Time?

Time is one of humankind’s unanswerable mysteries. Aristotle called time “the most unknown of unknown things.” What time is and even if it objectively exists are unanswerable questions. Time is intangible. There have been and will be countless theories about time. Many, including in science, are simply useful definitions or conventions, and each is looking at time in a particular way and for a particular purpose. This paper looks at a variety of significant perspectives from physics, philosophy and psychology. A key is to demonstrate that there are many different incomplete and subjective ways of looking at what ultimately is beyond our mental grasp.