The young Popper had been attracted to the apparent strength of theories such as Freud’s psychoanalysis and Adler’s ‘individual psychology’. These theories were regarded as capable of explaining virtually everything related to human behaviour as verifications were found to justify every advancement. Popper, however, was soon to discover a major flaw in them: they could not be refuted. Freud was therefore severely criticised by Popper for producing immunised theories against falsification. A theory unable to be falsified belongs, in Popper’s view, to a non-science. His drastic approach towards pseudo-science was also extended to Marxism, especially the Marxism that Neurath had brought to the Vienna Circle.Neurath interpreted Marxian ‘materialism’ as epsitemically equivalent to his own ‘physicalism’  and hailed Engels and Marx as having produced the foundations of a truly scientific study of society. In Popper’s opinion, this could not have been further from the truth. The problem with Marx was not only that he was considered a historicist, but that he was a utopian too.