In this rejoinder to the critical comments elicited by my essay “Existential Hypotheses,” I propose to deal first with the challenge coming from the avowedly different philosophical outlook of Professor Churchman. My other critics, Professors Frank, Hempel, Nagel and Ramsperger, on the whole, share my basic conception of the tasks of philosophy of science and epistemology, even if they dissent in one important respect or another from the special solution I suggested. But since I discern even in Professor Nagel's remarks (and possibly also between the lines of Professor Ramsperger's comments) a pragmatist or instrumentalist strain akin to the major contentions of Professor Churchman, it will be well to begin with a defense and further clarification of my underlying point of view. Only after this restatement of my platform will I undertake to defend semantic realism against the specific criticisms advanced by the last four authors.