The butterfly effect is a term used to describe the principles of nonlinearity and sensitivity to initial conditions, which hold that a nonlinear equation can have solutions that are irregular. The irregularity results in small changes being amplified by the nonlinear nature of the system. This means that if the initial state of the nonlinear system is changed only slightly, one cannot predict the difference in how each system will evolve over time. One often-cited example of the effects of nonlinearity and sensitivity to initial conditions was given by the meterologist, Ed Lorenz. He explained, mathematically, why predicting the weather with precision is impossible. Lorenz demonstrated that two virtually identical weather systems will behave differently over time due to their complex, nonlinear nature and due to inputs from the environment that are infinitely small. He suggested, somewhat tongue-in-cheek, that even the flapping wings of a butterfly could result in a tornado because of nonlinear processes at work even with the smallest factors causing the weather.