ANDRZEJ MOSTOWSKI AND PHILOSOPHY OF MATHEMATICS Jan Wolenski (Jagiellonian University, Kraków, Poland) The Polish attitude to metamathematics, shared by most Polish logicians was (and is) guided by two principles: (a) all commonly accepted mathematical methods should be applied in metamathematical investigations; (b) metamathematical research cannot be limited by any a priori accepted philosophical standpoint. On the other hand, mathematics has own genuine philosophical problems, which should not be neglected by mathematicians. In particular, although metamathematical results do not solve philosophical controversies about mathematics, yet the former illuminate the latter. Tarski was an extreme example of this practice. He used all admissible mathematical methods in his logical works, in particular, infinitary ones, usually associated with Platonism in the philosophy of mathematics. On the other hand, Tarski had explicit sympathies to empiricism, nominalism, reism and finitism (he even called himself "a tortured nominalism"). In general, Mostowski inherited his general philosophical attitude from Tarski. He was very sensitive to philosophical problems in mathematics and considered them as important. Although Mostowski stressed that there is no hope in achieving the solution of such questions, he yet insisted that should be illuminated by mathematical treatment of them. He freely used infinitary methods and strongly insisted that no formal work should be limited by philosophical assumptions. On the other hand, he had some sympathy to constructivism and related views.