Marx had warned against “the opium of religion”, something to distract the working classes from their class exploitation. Joseph Needham warned that there was also a danger that “the opium of science” was replacing the opium of religion in the twentieth century. People could be too optimistic that science alone could solve the great evils of human existence. In his opinion it could do a lot – provided you had a social reformist or socialist government – but what science lacked was a sense of the “numinous” or “the Holy”, and too many scientists lacked also a sense of humility.