Julian Huxley became the first President of the International Humanist and Ethical Union in 1952, and of Humanists UK in 1963. He saw Humanism as a replacement ‘religion’, and as such represented an important strand in post-war humanist thought. In a speech given to a conference in 1965 he spoke of the need for “a religiously and socially effective system of humanism.” And in his book Religion Without Revelation, he wrote:
“What the sciences discover about the natural world and about the origins, nature and destiny of man is the truth for religion. There is no other kind of valid knowledge. This natural knowledge, organized and applied to human fulfilment, is the basis of the new and permanent religion.” The book ends with the concept of “transhumanism”– “man remaining man, but transcending himself by realizing new possibilities of and for his human nature”.
In 1961 Julian Huxley brought together 25 distinguished people to present their view of existence in a book called The Humanist Frame. He wrote: “…the increase of knowledge is driving us towards the radically new type of idea-system which I have called Evolutionary Humanism…Humanism is seminal. We must learn what it means, then disseminate Humanist ideas, and finally inject them where possible into practical affairs as a guiding framework for policy and action.”
Wikipedia’s history of humanism.
Stanford University Encyclopedia article: Civic Humanism