Persons think. Bodies, time-slices of persons, and brains might also think. They have the necessary neural equipment. Thus, there seems to be more than one thinker in your chair. Critics assert that this is too many thinkers and that we should reject ontologies that allow more than one thinker in your chair. I argue that cases of multiple thinkers are innocuous and that there is not too much thinking. Rather, the thinking shared between, for example, persons and their bodies is (...) exactly what we should expect at the intersection of part sharing and the supervenience of the mental on the physical. I end by responding to the overcrowding objection, the personhood objection, the personal-pronoun reference problem and the epistemic objection. (shrink)

Are a statue and the lump of clay that constitutes it one object or two? Many philosophers have answered ‘two’ because the lump seems to have properties, such as the property of being able to survive flattening, that the statue lacks. This answer faces a serious problem : it seems that nothing grounds the difference in properties between colocated objects. The statue and lump are in the same environment and inherit properties from the same composing parts. But it seems that (...) differences in properties should be grounded. For this reason, philosophers including Mark Heller, Dean Zimmerman, Theodore Sider, Trenton Merricks, and Eric Olson have rejected the answer ‘two’. -/- I offer a solution to the grounding problem, in order to revive the traditional account. I argue that extrinsic relations contribute to the supervenience base of many kinds or sorts, and these extrinsic relations ground differences between colocated objects, such as statues and lumps of clay, human beings and lumps of tissue, and planets and masses of matter. The same collection of parts can stand in more than one extrinsic relation, with each relation grounding the composition of a distinct kind of object. In cases in which this happens, the properties of each object differ from the properties of other objects that share the same parts. (shrink)

To hold that only one conscious thing is sitting in your chair, philosophers have appealed to maximality: If a property M is maximal, then anything that has property M does not have large proper parts that have property M. Philosophers have said that ordinary objects are maximal, including houses, cats, rocks, and have argued by analogy that consciousness is maximal. I argue that the maximality principle mistakenly excludes some members of a kind. Thus, it is not the correct principle to (...) explain why, for example, you are conscious but the proper part that is all-of-you-but-your-arm is not conscious. (shrink)

In David Lewis’s famous ‘Many, but Almost One’, he argues that when objects of the same kind share most of their parts, they can be counted as one. I argue that mereological overlap does not do the trick. A better candidate is overlap in function. Although mereological overlap often goes hand-in-hand with functional overlap, a functional approach is more accurate in cases in which mereology and function are teased apart. A functional approach also solves a version of the problem of (...) the many that Lewis thought was immune to the Almost-One solution. (shrink)