"Openness of mind means accessibility of mind to any and every consideration that will throw light upon the situation that needs to be cleared up, and that will help determine the consequences of acting this way or that. Efficiency in accomplishing ends which have been settled upon as unalterable can coexist with a narrowly opened mind. But intellectual growth means constant expansion of horizons and consequent formation of new purposes and new responses. These are impossible without an active disposition to welcome points of view hitherto alien; an active desire to entertain considerations which modify existing purposes. Retention of capacity to grow is the reward of such intellectual hospitality. The worst thing about stubbornness of mind, about prejudices, is that they arrest development; they shut off the mind from new stimuli. Open-mindedness means retention of the childlike attitude; closed-mindedness means premature intellectual old age."