The article presents some aspects of Whitehead's criticism of modern epistemology and his attempts to resolve them. Whitehead is in agreement with modern philosophers that we should accept the so-called subjectivist turn. According to this view a philosopher should start his investigations with the content of his conscious experience. But Whitehead thinks that this revolutionary postulate cannot be reconciled with substantialism, broadly accepted by modern epistemologists. Thus he maintains that we should drop this inadequate ontological background and replace it with eventism. Yet this proposal is very controversial and in the paper the author analyzes basic problems connected with it.