  However, Vasubandhu's most compelling proof for idealism appeals to  the method of mereological reduction: wholes, being merely  collections of minimal parts, do not actually exist as perceived. But wholes, which are extended objects, must necessarily be made of  parts, the ultimate building blocks of which are the atoms. And since atoms, conceived as partless point-instant are ultimately  insubstantial, the realist argument for the existence of material  objects as conglomerates of parts must be false (VVS ad  11–14; for detailed discussion of some of these arguments, see  Kapstein 1988; Tola &amp; Dragonetti 2004, 98–110; Gold 2006).