There is necessarily a plurality of interpretations

It is possible, for example, to interpret 'history' as the history of class struggle, or of the struggle of races for supremacy, or as the history of religious ideas, or as the history of the struggle between the 'open' and the 'closed' society, or as the history of scientific and industrial progress. All these are more or less interesting points of view, and as such perfectly unobjectionable. But historicists do not present them as such; they do not see that there is necessarily a plurality of interpretations which are fundamentally on the same level of both suggestiveness and arbitrariness (even though some of them may be distinguished by their fertility – a point of some importance). Instead, they present them as doctrines or theories, asserting that 'all history is the history of class struggle', etc. And if they actually find that their point of view is fertile, and that many facts can be ordered and interpreted in this light, then they mistake this for a confirmation, or even for a proof, of their doctrine.

Karl Popper, The Poverty of Historicism (Routledge Classics, 2002) p. 140