 says it all: nothing would be part of anything else and parthood would collapse to identity. (This account is sometimes referred to as mereological nihilism, in contrast to the mereological universalism expressed by (P.15i); see van Inwagen 1990:  72ff.[25]  Van Inwagen himself endorses a restricted version of nihilism, which leaves room for composite living things. So does Merricks 2000, 2001, whose restricted nihilism leaves room for composite conscious things.)