J. J. Katz in “The Problem of Induction and its Solution” argues that not only a validation but also a vindication of induction is impossible. In the course of his argument a number of interesting issues arise about what is actually required for a satisfactory vindication. The aim of those who have sought to provide a vindication for induction has been to show that it is the most satisfactory means for forming expectations about the future; they have accepted the impossibility of showing that induction must, or will probably, lead to true predictions. Feigl gives a general characterisation of vindication as an “argument concerning means with respect to ends” and contrasts it to validation which is a justification of a knowledge claim by establishing it as true or probably true. We cannot validate the rules of induction but we can give a vindication of the adoption of these rules ([1], pp. 136-7). Katz accepts Feigl's distinction in general terms but proposes some modifications to meet certain defects which he believes to be present in the latter's account. Katz distinguishes two senses of vindication, an “expediency vindication” which “establishes a justificandum as a suitable means,” while a “preferability vindication” “establishes the justificandum as the preferable means for achieving the end.” An expediency vindication shows that the proposed means is a sufficient condition for achieving the end in view, but it need not establish this means as necessary to achieve this end. A preferability vindication will establish the means as necessary to achieve this end in the best way ([2], pp. 26-8). He then proceeds as follows: “an argument which demonstrates that a justificandum is a necessary condition—but only a necessary condition—for achieving the relevant end is not a real vindication.” He holds that the vindication of a certain means must show at least that it will achieve the end sought, and preferably that it is the best way of achieving this end ([2], p. 28).