While reading The Unbearable Lightness of Being, Kundera wrote that happiness is repetition, when speaking of Karenin, the dog. These words have stuck with me. Kundera starts off by rejecting Nietzsche's philosophie of eternal return, saying that human lives are linear and do not repeat themselves for all of eternity, this Linear movement is what makes humans unbearably light or in my terms without purpose. Karenin, on the other hand, gets repetition in her life, Kundera says this gives a life heaviness or for me a purpose.
Karenin and all animals were not exiled from paradise, as Kundera puts it, "dogs were never expelled from Paradise. Karenin knew nothing about the duality of body and soul and had no concept of disgust"(Kundera 297). Previously Tereza has shown her strained attempts to separate her soul from her body by looking endlessly in the mirror. Kundera says that Karenin does not have to struggle with this rumination of self.
Karenin gets what most humans search for all their lives, happiness, this is why I find what Kundera wrote so powerful. The only way to be happy is to not be human, because humans cannot live in the same circular patterns as animals do, how Karenin does in the novel or how paradise in Genesis was, any attempt would be futile. Humans can never be happy.