Abstracting behaviour out so that it can be shared by differing objects is a useful thing to be able to do. Putting shared behaviour (and maybe also assertions

Abstracting behaviour out so that it can be shared by differing objects is a useful thing to be able to do. Putting shared behaviour (and maybe also assertions as to the structure of 'instances') in another object and calling it a 'class' is one way to achieve that -- but not the only way. If you liked this I would recommend reading "The Treaty of Orlando" (DOI 10.1.1.55.482) and also anything you can get your hands on about a small forgotten language by Antero Taivalsaari called "Kevo". Kevo was a prototype based OO language without any delegation or 'parent' slots. Every object was self-contained and carried around within it all of the functionality it needed. Functionality was shared by copying, and shared behaviour was not reified into a separate object (whether called a 'class' or not)