Santos takes as his starting point George Berkeley"s insight that there cannot be an object without a perceiver - that to be is to be perceived. He then develops a naturalistic account in which this insight is the core element. This evolutionary account of the relationship between perceivers and the objects that they perceive entails that there are no objects without a perceiver. However, it also entails that unperceived objects are not annihilated when unperceived.