"These bodies which now we wear belong to the lower animals; our minds have already outgrown them; already we look upon them with contempt. A time will come when Science will transform them by means which we cannot conjecture, and which if explained to us we would not now understand, just as the savage cannot understand electricity, magnetism, steam. Disease will be extirpated; the causes of decay will be removed; immortality will be invented. And then the earth being small, mankind will emigrate into space and will cross airless Saharas which separate planet from planet, and sun from sun. The earth will become a Holy Land which will be visited by pilgrims from all quarters of the universe. Finally, men will master the forces of Nature; they will become themselves architects of systems, manufacturers of worlds. Man will then be perfect; he will be a creator; he will therefore be what the vulgar worship as God."
She explains however that this religion of science is no longer conceivable: "In these latter days of deep disillusionment, now that we have learnt, by the bitter experience of the Great War, to what vile uses the methods and results of science may be put, when these are inspired and directed by brutal instinct and base motive, it is hard to understand the naive belief of the most original and vigorous minds of the 'seventies and 'eighties that it was by science, and by science alone, that all human misery would be ultimately swept away."
And yet, this "naive belief" survived well into the 20th century among Science Fiction writers. Are SF writers just behind the times? Personally I suspect it's more that so many of the writers were Americans, and the impact of World War I, and later World War II, was never really felt in the same way in the US. Wikipedia suggests almost 10 million combat casualties in WWI of which only 116,000 were Americans; if the US had some proportion of casualties to population as the rest of the combatants, it would've been more like a million US casualties, ten time as many... and that's even before civilian deaths.