In this paper, first of all, I want to give a criterion for the perceivability of higher-level properties, i.e., the properties that depend for their own instantiation on the instantiation of low-level properties (colors, shapes, sounds, textures …); namely, conditions that are necessary and jointly sufficient in order for such a property to be perceivable. Here it is: the higher-level property is given i) immediately; ii) via a grouping operation that involves a perceptual form of attention Moreover, I want to show why some candidate higher-level properties fulfill it and some other such candidates don’t (they are only pseudo-perceivable).