The scientific approach, then, is not merely a matter of taste for humanists, to be applied or ignored at will. It is, instead, integral to humanism, for it is necessarily implied by our governing premises of naturalism and human distinctiveness. It is true that, periodically, the foundations of our movement have been attacked from within by the temporary appeal of Romanticism and subjectivism. These were the people who realized that the authenticity and very survival of a plant depends on the integrity of its root system. Their beliefs about the nature, sources and justification of knowledge are very different from those at the roots of humanism, however, and that difference is crucial.
Humanists identify a second aspect of human distinctiveness as our creative capacity.
We believe that the human species has evolved an imagination that allows us to envision possibilities not immediately available in past or current experience. It is this recognition that lies behind our desire to celebrate the worth of our species' imaginative and aesthetic products such as architecture, music, literature and the visual arts. We cherish all the magnificent creations that have enriched world culture throughout the centuries. We believe that these are grounded in the totality of the experience of the human race, from time immemorial. We recognize no other source.