"It is difficult, however, to avoid the feeling that in this mild latter-day anarchism of Kropotkin something has been lost of that fierce dynamic of revolt which animated the anarchism of Bakunin. Bakunin's indignation at the wickedness of the tyrant was no doubt accompanied by a naive faith in the constructive capacity and untutored goodness of the masses. In Kropotkin this faith has got mixed up with the Victorian belief in the inevitability of progress. His anarchism, no less than Marx's communism, claimed to have a scientific foundation. It was "more than a mere mode of action or a mere conception of a free society"; it was "part of a philosophy, natural and social", and "must be treated by the same methods as natural sciences". In pursuit of this conception Kropotkin wrote what was once probably the most famous of all his works, Mutual Aid, in which he demonstrated, in contradiction to the Darwinian theory of progress through the struggle for existence, that animal life, as well as primitive human societies, survived not through processes of mutual destruction but through processes of cooperation. Towards this conception human society was constantly and continuously evolving. To-day such conceptions seem as faded and irrelevant as the pseudo-scientific political applications of Darwinism which they were intended to refute. And with them goes the pseudo-scientific optimism about the progressive evolution of human nature which was the basis of Kropotkin's anarchist creed."