The term "a priori" is taken from Kant and has a special meaning in his system of thought, but the problem of the a priori, that is, the question of what is first in the order of knowledge, takes various forms in the thinking of contem-porary philosophers. For example, the question of what is first is manifested in the problem of "the given," which has been formulated by men such as C. I. Lewis, Hans Reichenbach, Everett W. Hall,¹ and others. The question of what is first also comes up in the study of basic philosophical metaphors. For example, the philosopher Max Black² and the French phenomenologist Mikel Dufrenne,³ among others, have probed the basis of rudimentary philosophical conceptions in their linguistic studies of models and metaphors. Their thinking gives rise to questions such as this: if the study of philosophical meta-phors and scientific models takes us beyond model and metaphor to their origins in creative acts of genius, to what structural basis, then, can we look for the grounding of our conceptual world or even our linguistic world ? To these and other epistemological questions, as well as those concerning the foundations of logical systems, Carl G. Jung's thought might be illuminating.