A method for positioning a substage (9), supported by a main stage (5), relative to a reference object, the substage moveable in a direction (7) between a first and second position relative to the main stage. The method includes positioning the first stage using a passive force system that is activated by positioning the main stage. The passive force system includes two magnet systems (119, 121), each magnet system being configured to apply a force in the direction to the first stage with respect to the second stage in a non-contact manner, the forces resulting in a resultant force applied to the first stage in the direction by the passive force system. A magnitude and/or a direction of the resultant force depends on the position of the first stage relative to the second stage, and the first stage has a zero-force position between the first and second position in which the resultant force is zero.