THE feelings of reality and unreality which often attach to certain psychological phenomena are of great importance; for they indicate the more or less considerable degree of activity which accompanies these phenomena. A feeling of unreality is often observed in connection with the perception of objects among patients who might be called psychasthenic doubters. In several places I have had occasion to point out that this feeling does not depend on a disorder in sensation but on the waning of the tendency to act in response to these perceptions. The same evidence has occurred to me in even a simpler form while studying the unreal memories of these very patients at the J. J. Rousseau Institute at Geneva;* and the same problem might be examined in a somewhat inverse manner in trying to understand the exaggerations of the feeling of reality which in every case accompanies the memories. A rather striking observation suggests to us these reflections on the degree of reality which we attribute more or less correctly to our representations.