The article presents Mill's response to Hume's criticism of induction, and Mill's attempt to justify induction against accusation of vicious circle. The notion of cause used by Mill, and essential for his methodological views, seems to be unclear or involved in a vicious circle. Recent reconstructions of scientific procedures expose a number of vicious circles in science, e.g. the relation between theory and observation, which seem to be mutually based one on another. Mill's example shows a realistic approach to these problems.