Text this: Why is schrödinger's equation linear?

 _    _      ___     _____      _____     ______  
| \  / ||   / _ \\  |  __ \\   |  ___||  /_   _// 
|  \/  ||  / //\ \\ | |  \ ||  | ||__      | ||   
| .  . || |  ___  ||| |__/ ||  | ||__     _| ||   
|_|\/|_|| |_||  |_|||_____//   |_____||  /__//    
`-`  `-`  `-`   `-`  -----`    `-----`   `--`