In their penetrating and admirably lucid discussion, “Purposeful and Non-purposeful Behavior,” Professors Rosenblueth and Wiener have considerably clarified the point of view expressed in their earlier paper dealing with the conception of purpose, and recently criticized by me. But while their discussion thus removes some of the difficulties which, I think, stood in the way of acceptance of their position, there yet remain fundamental questions which I do not believe have been adequately dealt with.These authors rebuke me, with justice, for (...) not indicating my own conception of purposiveness, and they add that this omission weakens my criticisms of their view. That the omission detracts from the interest of my paper is doubtless correct, but that it weakens my criticisms of their position is not similarly obvious. I shall, at any rate, attempt to rectify this defect in the present discussion. (shrink)