  Here I will just mention one objection that many have felt is telling against the relative identity view. Let w be a water droplet that is in s1 but not s2. The relative identity solution says that the droplets in s1 compose an object o1, and the droplets in s2 compose an object o2, and though o1 and o2 are different fusions of water droplets, they are the same cloud. Call this cloud c. If o1 is the same cloud as o2, then presumably they have the same properties. But o1 has the property of having w as a part, while o2 does not. Defenders of the relative identity theory here deny the principle that if two objects are the same F, they have the same properties. Many theorists find this denial to amount to a reductio of the view.