Mystics through the ages have spoken of out-of-body experiences, often involving progress towards an experience of void, as the mind releases itself from sensory stimuli and achieves a higher lucidity characterized by Meister Eckhart as a state of unknowing'. Certain contemporary forms of Buddhist- or Hindu-inspired meditation, popularized in the West from the 1960s onwards, have made a central tenet of the ancient lesson of detachment from the senses, and have promoted the attempt to reach a state of consciousness that is free from the material and the bodily. It implies that in sensual abstinence there may be abundance, and comes with the corollary that, in the exercise of spiritual meditation, a controlled reduction of sense perceptions may enable an expansion of awareness and sensitivity. Flaubert's reaction on reading Louis Lambert in December 1852 shows that he identifies strongly with that state of physical inertia and withdrawal into heightened mental activity that Balzac describes in his 1832 novel.