Am I mistaken in thinking of literary modernism as being defined exclusively by experimentation with form? Does modernism also feature a specific kind of content?
For example, Kafka is described on Wikipedia as a modernist writer, but, as far as I'm familiar with Kafka (which is not very much) he doesn't experiment with form. In terms of form, he is no different than a realist writer.
Is the non-realist content of his novels sufficient to class him as a modernist, even if formally his novels are no different than realist novels?