I T HAS BECOME customary to include under the one name of "existentialism" several philosophies which, in truth, differ considerably from each other. This gives rise to various misunderstandings. In fact, only one of the more prominent "existentialist" calls his philosophy by this name. Others, such as Heidegger and Marcel, have emphatically declared that their philosophies should not be designated as existentialistic. It is important to take account of this circumstance if one wants to arrive at an adequate appraisal of these several currents in contemporary philosophy.
Of course, the use of the one common name is, at first sight, not unjustified. All these thinkers speak of "existence," though as we shall see, not at all in the same sense. All are concerned with individual man, but again in different ways. Finally, these philosophies appeared, or seemed to appear, all in the years after the first and again after the second World War. Because of this, existentialism has been often viewed as the product of the post-war situation. This is, however, a superficial opinion. For not only did ideas and interests manifest themselves earlier, ideas which then were incorporated into these several philosophies, but one finds statements of a clearly "existentialist" nature prior to World War I. Gabriel Marcel published an article of definitely existential tendency as early as 1912, and Ortega y Gasset formulated one of the basic notions of these philosophies in spring 1914. 1____________________