Contemporary Iranian politics has always been characterized by a struggle between the so-called reformists and conservatives，and the political debate between the two sides is not only reflected in their general policies but also in their fundamental differences in political theory and ideological foundations. In 1985，the work of British philosopher Karl Popper sparked a fierce and enduring debate in Iran. Since Popper’s political theory is based on his philosophical views of science，the controversy over Popper also links the views of science of Iranian intellectuals to political theory. Therefore，the problem of science are of great importance in contemporary Iranian political theory and even form the basis of some political theories. Reza Davari and Abdulkarim Soroush are the key figures on opposite sides of this debate，and their political theories and proposals cannot be separated from their discussion of the truthfulness of science. The debate over science not only demonstrates the centrality of truth and reason to Iranian political theory，but also shows that Iran’s domestic political discourse is influenced and conditioned by global knowledge production.