"The psychology of a complex mind must differ almost as much from that of a simple, mechanized mind as its psychology would from ours; because something that must underlie and perhaps be even greater than sex is involved."

“If Engels had not been the constant companion in arms of Marx in the revolutionary struggles of the 19th century, there is no doubt that he would be remembered chiefly as one of the foremost scientist-philosophers of the century. It was an ironical tribute paid to the correctness of his views as to the relations between politics and ideology that he suffered complete neglect from the scientists of the Victorian age. But time now has taken its revenge, and Engels’ contemporary views on 19th century science seem to us now in the 20th far more fresh and filled with understanding than those of the professional philosophers of science of his day, who for the most part are completely forgotten, while the few that linger on, such as Lange and Herbert Spencer, are only quoted as examples of the limitations of their times.”

“In science men have learned consciously to subordinate themselves to a common purpose without losing the individuality of their achievements. Each one knows that his work depends on that of his predecessors and colleagues, and that it can only reach its fruition through the work of his successors. In science men collaborate not because they are forced to by superior authority or because they blindly follow some chosen leader, but because they realize that only in this willing collaboration can each man find his goal.”

“One of the questions on which clarity of thinking is now most necessary is that of the relation between the methods of science and of Marxist philosophy. Although much has already been written on the subject, yet there is still an enormous amount of confusion and contradictory statement.”

“In the decade after the war Freud’s theories dominated the narrow circles of British intellectuals. His psycho-analysis was accepted warmly for many reasons. It was new and exciting, it was shocking, it debunked religion and morals, it promised an internal liberation from all restraints. Nevertheless, it was essentially a creed of escape into an inner world of complexes and repressions and away from social and economic realities.”

“Life is a partial, continuous, progressive, multiform and conditionally interactive self-realization of the potentialities of atomic electron states.”

“There are two futures, the future of desire and the future of fate, and man's reason has never learnt to separate them. Desire, the strongest thing in the world, is itself all future, and it is not for nothing that in all the religions the motive is always forwards to an endless futurity of bliss or annihilation. Now that religion gives place to science the paradiscial future of the soul fades before the Utopian future of the species, and still the future rules. But always there is, on the other side, destiny, that which inevitably will happen, a future here concerned not as the other was with man and his desires, but blindly and inexorably with the whole universe of space and time. The Buddhist seeks to escape from the Wheel of Life and Death, the Christian passes through them in the faith of another world to come, the modern reformer, as unrealistic but less imaginative, demands his chosen future in this world of men.”