Hysteresis is the dependence of a system’s current state on past input values. The dependence arises because its history affects the value of an internal state. With all complex systems and dissipative systems, there is a strong issue of time and this importance of time can be ascribed to path dependency and hysteresis, that both tell us in a general sense that history matters. Hysteresis greatly emphasizes the role of history in a system, and demonstrates that the system has memory in that its dynamics are shaped by past events.