Time : Time is money.
Since the days of Aristotle, and even before, philosophers have tried to explain the idea of time. Throughout history, humans have been known to work with multiple time structures and variants. Unlike all other living beings, only humans exist in a constant present, making this one of human civilizations distinguishing characteristics.
More recently, modern philosophy has continued to question if time is real or unreal. Moreover, there has also emerged a whole host of other time-related philosophical issues, including whether time is dynamic or static, whether the present is instantaneous or lengthy, whether past and future exist, how things live over time, etc. Many of modern science s groundbreaking ideas have also given rise to new philosophical insights and assumptions on the nature of time.