 However, Linnebo does not identify being abstract with being thin (2012, 147), for there are thin objects in a relative sense that are not abstract, namely those that make no substantial demands on the world beyond those introduced in terms of some antecedently given objects. The mereological sum of your left hand and your laptop makes no demand on the world beyond the demands of its  parts.[19]  Instead, he suggests that abstract objects are those that are thin and that have a shallow nature. The notion of shallow nature is meant to capture “the intuitive idea that any question that is solely about \(F\text{s}\) has an answer that can be determined on the basis of any given specifications of these \(F\text{s}\)” (2018, 192–195). For example, directions have a shallow nature because any question about directions (e.g., are they orthogonal, etc.?) can be determined solely on the basis of the lines that specify them. Shapes have a shallow nature because any question about them (e.g., are they triangular, circular, etc.?) can be determined solely on the basis of their underlying concrete figures. By contrast, mereological sums of concrete objects are not shallow because there are questions about them that cannot be answered solely on the basis of their specifications; for instance, the weight of the mereological sum of your laptop and your left hand depends not only on their combination but also on the gravitational field in which they are  located.[20] 