Abstract: I will present an argument for property dualism. The argument employs a distinction between having a concept of a property and grasping a property via a concept. If you grasp a property P via a concept C, then C is a concept of P. But the reverse does not hold: you may have a concept of a property without grasping that property via any concept. If you grasp a property, then your cognitive relation to that property is more intimate then if you just have some concept or other of that property. To grasp a property is to understand what having that property essentially consists in.