Logic & Philosophy of Science Colloquium

For a hundred years and more, ever since Russell's paradox brought the system on which Frege hoped to found mathematics crashing down, it has been a dream of philosophers and logicians to find some comparatively simple restriction that would on the one hand bar paradox, but on the other hand permit the development of arithmetic and higher mathematics. Recent work of Harvey Friedman may bring this century-old dream to fulfillment at last. The present paper aims to provide an elementary introduction to that work.