  Some theorists have argued that the underlying cause of the problem is that we have the wrong theory about the relation between parts and wholes. Peter van Inwagen (1990) argues that the problem is that we have assumed that the parthood relation is determinate. We have assumed that it is always determinately true or determinately false that one object is a part of another. According to van Inwagen, sometimes neither of these options applies. He thinks that we need to adopt some kind of  fuzzy logic  when we are discussing parts and wholes. It can be true to degree 0.7, for example, that one object is part of another. Given these resources, van Inwagen says we are free to conclude that there is exactly one cloud in the sky, and that some of the ‘outer’ water droplets are true of it to a degree strictly between 0 and 1. This lets us keep the intuition that it is indeterminate whether these outlying water droplets are members of the cloud without accepting that there are millions of clouds. Note that this is not what van Inwagen would say about this version of the paradox, since he holds that some simples only constitute an object when that object is alive. For van Inwagen, as for Unger, there are no clouds, only cloud-like swarms of atoms. But van Inwagen recognises that a similar problem arises for cats, or for people, two kinds of things that he does believe exist and he wields this vague constitution theory to solve the problems that arise there.