Again, while he sets forth the historical succession of systems of belief and forms of political society, and places in the strongest light those imperfections in each which make it impossible that any of them should be final, this does not make him for a moment unjust to the men or the opinions of the past. He accords with generous recognition the gratitude due to all who, with whatever imperfections of doctrine or even of conduct, contributed materially to the work of human improvement. In all past modes of thought and forms of society he acknowledged a useful, in many a necessary, office, in carrying mankind through one stage of improvement into a higher. The theological spirit in its successive forms, the metaphysical in its principal varieties, are honoured by him for the services they rendered in bringing mankind out of pristine savagery into a state in which more advanced modes of belief became possible. His list of heroes and benefactors of mankind includes, not only every important name in the scientific movement, from Thales of Miletus to Fourier the mathematician and Blainville the biologist, and in the aesthetic from Homer to Manzoni, but the most illustrious names in the annals of the various religions and philosophies, and the really great politicians in all states of society.[20] Above all, he has the most profound admiration for the services rendered by Christianity, and by the Church of the middle ages. His estimate of the Catholic period is such as the majority of Englishmen (from whom we take the liberty to differ) would deem exaggerated, if not absurd. The great men of Christianity, from St Paul to St Francis of Assisi, receive his warmest homage: nor does he forget the greatness even of those who lived and thought in the centuries in which the Catholic Church, having stopt short while the world had gone on, had become a hindrance to progress instead of a promoter of it; such men as Fénélon and St Vincent de Paul, Bossuet and Joseph de Maistre. A more comprehensive, and, in the primitive sense of the term, more catholic, sympathy and reverence towards real worth, and every kind of service to humanity, we have not met with in any thinker. Men who would have torn each other in pieces, who even tried to do so, if each usefully served in his own way the interests of mankind, are all hallowed to him.