“Animalism” is the philosophical foundation and political law by which the animals live. Napoleon changes the commandments over the course of the novel. Squealer is in charge of writing these “commandments” on the side of the barn. When the animal revolution begins, one of the tenets is “All animals are comrades.” Animalism is a version of communism. Over time, Napoleon takes over, becomes a dictator and the idea of communal equality among the animals eventually fades.
Eventually, one of the commandments reads “All animals are equal, but some are more equal than others.” Napoleon periodically orders changes to the commandments of Animalism to suit the changes he thinks he has to make to sustain his regime and power. So, Animalism is a philosophy and a political ideology. Like all philosophies and political ideologies, different people (or animals) will interpret them in different ways. For instance, democracy has manifested in many different forms in many different countries. Orwell wrote this novel as an allegory of the Russian Revolution. In both cases, the hope was that the implementation of communism would lead to a better society. And in both cases, that implementation was destroyed by the corruption of those in power. The original commandments clearly separated animals from humans. The analog to the Russian revolution was a separation between communism and capitalism. By the end, Napoleon and his cohorts begin to behave like humans. This completes the destruction of the purity and equality of the revolution.