subjects with no preconceptions about the drug to conduct experiments, and these became very difficult to find. Philosophy and religion Huxley's friend and spiritual mentor, the Vedantic monk Swami Prabhavananda, thought that mescaline was an illegitimate path to enlightenment, a "deadly heresy" as Christopher Isherwood put it. Other thinkers expressed similar apprehensions. Martin Buber Martin Buber, the Jewish religious philosopher, attacked Huxley's notion that mescaline allowed a person to participate in "common being", and held that the drug ushered users "merely into a strictly private sphere". Buber believed the drug experiences to be holidays "from the person participating in the community of logos and cosmos—holidays from the very uncomfortable reminder to verify oneself as such a person." For Buber man must master, withstand and alter his situation, or even leave it, "but the fugitive flight out of the claim of the situation into situationlessness is no legitimate affair of man." Robert Charles Zaehner Robert Charles Zaehner, a professor at Oxford University, formed one of the fullest and earliest critiques of The Doors of Perception from a religious and philosophical perspective. In 1954, Zaehner published an article called The Menace of Mescaline, in which he asserted that "artificial interference with consciousness" could have nothing to do with the Christian "Beatific Vision". Zaehner expanded on these criticisms in his book Mysticism Sacred and Profane (1957), which also acts as a theistic riposte to what he sees as the monism of Huxley's The Perennial Philosophy. Although he acknowledged the importance of The Doors of Perception as a challenge to people interested in religious experience, he pointed out what he saw as inconsistencies and self-contradictions. Zaehner concludes that Huxley's apprehensions under mescaline are affected by his deep familiarity with Vedanta and Mahayana Buddhism. So the experience may not be the same for others who take the drug and do not have this background, although they will undoubtedly experience a transformation of sensation. Zaehner himself was a convert to Catholicism. That the longing to transcend oneself is "one of the principal appetites of the soul" is questioned by Zaehner. There are still people who do not feel this desire to escape themselves, and religion itself need not mean escaping from the ego. Zaehner criticises what he sees as Huxley's apparent call for all religious people to use drugs (including alcohol) as part of their practices. Quoting St Paul's proscriptions against drunkenness in church, in 1