Phenomenalism differs from idealism in that it holds that objects exist insofar either as they are perceived or as it is possible to perceive them. Phenomenalism is thus a weaker theory than idealism. Whereas idealists are committed to the idea that an object that is not perceived does not exist, phenomalists can allow that such objects exist insofar as it is possible to perceive them. They therefore have no need to invoke God to explain objects disappearing and reappearing when people cease and recommence perceiving them, as the idealist does.