The mere physical act of sitting down to practise meditation is both a symbolic gesture of withdrawal from the world and an actual severance from it. Each time it is done the meditator temporarily renounces his outer personal life, renders himself oblivious of it and of the world in which it is lived. What other withdrawal is needed? Is this not enough? Therefore anyone may continue to remain a householder and need not take monastic vows, may be active in the world provided such daily periods of meditation successfully take him out of it.
-- Notebooks Category 4: Elementary Meditation > Chapter 1: Preparatory > # 50