In this paper, it is intended to propose a working hypothesis concerning the development of Communist ideology, especially with regard to its philosophical aspects. This hypothesis was formed in the course of an effort to understand what is changing and what does not change in Communist, and more especially, in Soviet doctrine.1 It has proved to be fruitful in its application.2 The hypothesis is briefly this: there are at least three different components in Communist ideology, and above all in Communist philosophy - the basic dogma, th$ systematic superstructure, and the declassified doctrines. The boundaries between these three components are not always clearly drawn, and there can be some difficulty in determining whether a partic ular doctrine belongs to the first or to the second, to the second or to the third group. Where it does belong, only the behavior of Soviet authorities and of Communist writers can indicate. But the hypothesis itself - namely the assumption that there are such classes of statements - helps consider ably in research, because it precisely focuses the attention upon the differences in the said behavior. Until recently (since 1947 and especially since 1950), the process of evolution in Soviet thought has consisted primarily in the fact that our three components have become apparent, while hitherto, everything - from the dogma of the future victory of Communism down to the illegitimacy of cybernetics - was thought to have the status of parts of equal significance in Soviet ideology. There is little in Soviet philosophical literature which would resemble our hypothesis as far as explicit divisions of ideology are concerned. But the practice seems to point very strongly towards the defacto recognition of such an articulation.