Autoloaders define ways to automatically include PHP classes in your code without having to use statements like require and include.
- PSR-4 would allow for simpler folder structures, but would prevent us from knowing the exact path of a class just by looking at the fully qualified name.
- PSR-0 on the other hand is chaotic on the hard drive, but supports developers who are stuck in the past (the underscore-in-class-name users) and helps us discern the location of a class just by looking at its name.